Moparts
Mushroom Tappet Cams
Posted By: Bighead440
Mushroom Tappet Cams - 03/21/10 05:34 PM
I am tasked with building a motor for my partner's '62 Valiant nostalgia gasser. It now has a 383 that he built, out of unwanted/leftover parts mostly (unported "906" heads w/stock valves and "077" dual springs, L2293F pistons, .533" hyd MoPar cam, Offy 1X4bbl tunnel ram, etc.), that runs
7.40s@96mph with a 4.10 Dana and a 5000 stall 8" converter. He wants to retain the tunnel ram, and hopefully stick with the same converter, but we are going to add 4.56 gears and a spool (SureGrip is dying). I was thinking of building a 496" 383 stroker or a 451-471" B-block motor with a 400 block and using one of my obsolete mushroom cams that I have never tried. I think one of these would fit the "old-school" character of the car perfectly, and sound wicked. I am aware of the "back-spotface" mods that some say you must do to the block, and a machinist buddy made me the bushing for the lifter bores to pilot the cutter, so I have the tooling. The heads will be Stealth aluminum units, ported to just over 300cfm @.600" lift, with the correct springs for the big flat tappet cams. For rockers we will be using R.A.S. bushed Isky iron rockers. I have a Racer Brown STX-60 (271@.050"-.632"-105LSA) and a "Mini-Express" (282@.050"-.654"-107LSA) and the "690" (290@.050-.690"-107LSA) both by MoPar all with new mushroom lifters. I need some input on the characteristics/peculiarities of these mushroom cams and a recommendation of which one might suit each displacement in our application. I tend to overcam and my partner is TOO conservative!
Thoughts??? RB
Posted By: Dodgem
Re: Mushroom Tappet Cams - 03/21/10 05:49 PM
My unwashed opinion is if you go 496 either of the big ones with that gear and 5000 stall. sure sounds like it will be fun.
from iski
"MUSHROOM LIFTER: Serves the same purpose as a regular lifter (flat tappet) but is a different shape. The face of the lifter (the area that contacts the cam) is of a larger diameter than that of the lifter body - . - it vaguely conforms to the shape of an inverted mushroom"
This guy might know some stuff
Postby andyf » Thu Nov 06, 2008 12:27 pm
I've run mushroom lifters in a BB Mopar before, in fact, that used to be a fairly standard setup 30 years ago. But that was back before Jesel had 1.85 rocker arms off the shelf for the BB Mopar. The mushroom lifter setup worked okay in the big Mopar engines but it was a bit of a pain to change cams.
Posted By: MR_P_BODY
Re: Mushroom Tappet Cams - 03/21/10 06:05 PM
I ran the 690 mushroom in a 383 YEARS ago, it made
real good power and it wanted to run high rpm
Posted By: Anonymous
Re: Mushroom Tappet Cams - 03/21/10 06:16 PM
The idea is simple. Mopars have always enjoyed the advantage of a larger diameter lifter--this really helps the cam and lifters live--we were never "using" the entire diameter and it made sure we did not have as much cam and lifter wear problems as other brands--Well...along comes the computer and cam selling guys and they designed cams that "use up" that extra diameter we had--they call the cams designed for the .904 lifter--sure they spec out better than old stuff and they may make a few more HP but...they give away the best thing we had going and cause lots of wear releated problems and you have to run MORE spring etc--nothing but trouble for a few more HP--Mopar knew way back that with big cams came big spring pressure and they went to the MAX with lifter diameter using the mushroom design--they intended on staying out front of the common wear problem--Simply..the mushroom design lets youy run big spring pressure needed with race lobes and be free from the wear issues--They should make them all that way again--oh..we got rollers now--forget that.
Posted By: Bighead440
Re: Mushroom Tappet Cams - 03/21/10 06:40 PM
Quote:
I ran the 690 mushroom in a 383 YEARS ago, it made
real good power and it wanted to run high rpm
Yeah, I'll bet! 
Our nostalgia rail with ported "915s", a Lunati 316/326-265/271@.050"-.576/.563"-108LSA solid flat-tappet, Offy TR w/2X660s on a .060" over 383 (394") 13:1 compression wanted 7200rpm every shift! 
With 1000gr+ pistons and beamed stock rods with WaveLoc bolts I was praying every pass!!! 
I hope the stroker nature of this build will tame that some, most of these were ground with Super Gas/ Super Stock type RB motors in mind (426-440) so I'll bet the bigger motor will love the fat lobes and the aluminum head's better flowing ports can surely use the over .600" lift... I think that STX-60 would be the BOMB with maxed-out iron heads on a serioud 383/400 though... 
RB
Posted By: atoetly
Re: Mushroom Tappet Cams - 03/21/10 11:04 PM
I've ran three different racer brown mushroom cams. One stx22 and two differnt stx42's with different lsa's I would like to try an stx 62 just for fun to see what it would do. As far as the spot face on the lifter bores go all I had to do to my old 440 block was clean up the casting at the bottom of the bores. My lifters are not the stock steel lifters and have a huge radius from the 1 inch face transitioning into the body so I had to make a chamfer at the bottom of the lifter bores to make them work? The only reason I had to do this was to get the lifters down in the bores so I could install the cam. Once the cam is installed the lifters never come close to that area of the block. My new world alumium block came with bushings that hung down so far we had to back spot face them flush with the boss and then make a chamfer. The best pass my car has made was in 07 when it ran a 9.62@ 138mph with a 60' of 1.28 The car then weighed 3170lbs had 496ci and I was running mufflers that always killed a tenth.
Posted By: Bighead440
Re: Mushroom Tappet Cams - 03/21/10 11:33 PM
Quote:
I've ran three different racer brown mushroom cams. One stx22 and two differnt stx42's with different lsa's I would like to try an stx 62 just for fun to see what it would do. As far as the spot face on the lifter bores go all I had to do to my old 440 block was clean up the casting at the bottom of the bores. My lifters are not the stock steel lifters and have a huge radius from the 1 inch face transitioning into the body so I had to make a chamfer at the bottom of the lifter bores to make them work? The only reason I had to do this was to get the lifters down in the bores so I could install the cam. Once the cam is installed the lifters never come close to that area of the block. My new world alumium block came with bushings that hung down so far we had to back spot face them flush with the boss and then make a chamfer. The best pass my car has made was in 07 when it ran a 9.62@ 138mph with a 60' of 1.28 The car then weighed 3170lbs had 496ci and I was running mufflers that always killed a tenth.
The STX-60 seems mild, I guess it has the velocity/rate-of-lift going for it, but not so much @.050" duration for a big block. Of course that 105LSA is gonna make it rattle! 
Sounds like you had a big enuff motor for the STX-62, and by the way, I have always wondered if Racer Brown supplied this cam to MoPar as their "MiniExpress" grind, or if they copied it, as their specs are almost identical. (?) 
I have been told before that the 328 dur."690" MoPar grind (supposedly 10hp better than the .650" mushroom 328deg. predecessor) specs out almost identical to the McCandless/Comp 324-.650" regular .904" solid. The guy that told me this is reputable and runs the .650" McCandless cam now, but he said the "690" was only .650" lift with 1.5 rockers. I put mine in a block and measured the lobe lift directly from the lobe and got .458" on both intake and exhaust lobes for #1 cylinder. That would be .458"x1.5=.687" (.690!), so maybe he mapped the older 328/.650, IDK.(???)
Thanks for your input! RB
Posted By: atoetly
Re: Mushroom Tappet Cams - 03/22/10 12:53 AM
The stx 42's have more duration @.050 (290) than the stx 62 (280) but the 42's have less lift 673 with 1.6 rockers. The stx 62 has 687 lift with 1.6 rockers. My first stx 42 had a lsa of 108 and my current one has a lsa of 110 don't sound like much but it gained me piston to valve clearance and also mellowed out the idle.
Posted By: cbarracuda
Re: Mushroom Tappet Cams - 03/22/10 01:51 AM
Mopar peformance 316 duration, 107 center line valve lift 654 intake and exhaust, made 640 hp in my old 440 stock stroke 906 home ported heads back in the 90s. The mini express has 328 duration and 690 lift and works better in light weight cars. I really like mushroom lifters cams and I am working on a new motor which is a small block 408 and Im going to use a mushroom cam that I found in this forum. Good luck with your project. The power is really close to a roller cam without the expensives and the maintenance.
If you want to sell your mini express send me a message.
Posted By: Bighead440
Re: Mushroom Tappet Cams - 03/22/10 02:47 AM
Quote:
The stx 42's have more duration @.050 (290) than the stx 62 (280) but the 42's have less lift 673 with 1.6 rockers. The stx 62 has 687 lift with 1.6 rockers. My first stx 42 had a lsa of 108 and my current one has a lsa of 110 don't sound like much but it gained me piston to valve clearance and also mellowed out the idle.
OK, I see, the STX-42 wasn't on the RacerBrown sheet I have. The 62 sounds similar to the "MiniExpress" that I have (314deg x.654" MoPar), but mine is on a 107deg LSA according to (erratic) MoPar. What did the 108LSA STX-42 idle at, 1200rpm??? What did you run for valvespring? I have some in mind... 
RB
Posted By: Bighead440
Re: Mushroom Tappet Cams - 03/22/10 03:14 AM
Quote:
Mopar peformance 316 duration, 107 center line valve lift 654 intake and exhaust, made 640 hp in my old 440 stock stroke 906 home ported heads back in the 90s. The mini express has 328 duration and 690 lift and works better in light weight cars. I really like mushroom lifters cams and I am working on a new motor which is a small block 408 and Im going to use a mushroom cam that I found in this forum. Good luck with your project. The power is really close to a roller cam without the expensives and the maintenance.
If you want to sell your mini express send me a message.
That was a rockin' 440 you had with 640hp and no roller cam!!!
I hate the way MoPar Performance mis-labels and cross-markets their stuff over the years. The same "MiniExpress" part number and description seems to have applied to at least three cams!!! Their own "bible" lists the LSA as 106-107deg !!! I have read in numerous magazines and book-compilations of mags where the same part number (ends in "588" IIRC) is described and listed as BOTH .654 and .690" lift and 314 AND 328 duration! Then in my latest "bible", in the text, not the charts, they say:"the new camshaft provides a 10hp increase at higher rpms than the .650" version of the 328 it replaces. This is not an easy task at this level, low end torque is reduced somewhat, a race torque converter must be used. Requires mushroom tappets, sold seperately..."
The .654" camshaft I have is a "MiniExpress", listed in the charts in the SAME bible!!! I doubted the .650" cam existed but I have seen them in independent publications and for sale on Ebay, where I got my 328/.690" that has a different part number and came WITH lifters. I think MoPar just threw the "Mini-Exp" name around referring to whatever they were selling at the moment. They are obviously from different manufacturers, as the 314/.654 is parkerized and has the grooved 4th journal like the STX-60 and the 328/.690 (confirmed by ME to be .687" lift w/1.5 rockers) is polished (non-parkerized) like all the other PurpleShafts were in that era (and still today I guess). I know it's alot of blabbing 
, but it is very confusing and hard to even get a recommendation because everyone thinks they have run a certain cam, but WHICH ONE WAS IT!!! If I decide to liquidate one, I'll let you know, you might want to send me a PM so I'll have an easier way to find you then. Thanks, RB
PS: I saw a MP mushroom LA cam "MaxVelocitor" or something to that effect on Ebay a while back. .670" lift, 110LSA, IIRC, is that the one you have? Just curious... 
Posted By: 40ford
Re: Mushroom Tappet Cams - 03/22/10 03:35 AM
A couple of comments from my experience of many years ago-----
We used both the Mopar .654" and .690" mushroom lifter cams. Neither required spot facing the underside of the lifter bores---you might want to check that before doing the machine work. Our experience was in 400" blocks only, the 383" may require it, I don't know.
Both Mopar cams worked good, but required serious head work---worked semi stock heads will not benefit from the the .654" or .690" cams.
The heads stall at a much lower lift. The engines did need to turn some RPM to work well----around 7800RPM.
BTW, Lunati also produced mushroom cams for the BB---and they worked really well with less lift and slightly more duration.
Another thing, don't get too crazy on valve spring pressures----180 on the seat and 400 across the nose works OK. And, loosen the lash .02-.03" to allow for more lifter rotation.
Check your rocker geometry real close----make sure the rocker sweep across the valve tip is centered and as short a sweep as possible.
Finally, use inner springs to break in the cam/lifter.
Posted By: cbarracuda
Re: Mushroom Tappet Cams - 03/22/10 03:48 AM
The mushroom cam with a 654 lift and a 316 duration is a different cam from what Mopar calls the mini express with 690 lift and a 328 duration. I was using the small mushroom because my car wieghts 3700 lbs with my in it, It was a 68 charger that ran 10.50s. The mushroom cam that I found in this forum had 630 lift with 1.5 rockers and it will have 652 with the 1.6 that I have on my small block. the only marks on the cam are mv102
Posted By: Bighead440
Re: Mushroom Tappet Cams - 03/22/10 03:57 AM
Quote:
A couple of comments from my experience of many years ago-----
We used both the Mopar .654" and .690" mushroom lifter cams. Neither required spot facing the underside of the lifter bores---you might want to check that before doing the machine work. Our experience was in 400" blocks only, the 383" may require it, I don't know.
Both Mopar cams worked good, but required serious head work---worked semi stock heads will not benefit from the the .654" or .690" cams.
The heads stall at a much lower lift. The engines did need to turn some RPM to work well----around 7800RPM.
BTW, Lunati also produced mushroom cams for the BB---and they worked really well with less lift and slightly more duration.
Another thing, don't get too crazy on valve spring pressures----180 on the seat and 400 across the nose works OK. And, loosen the lash .02-.03" to allow for more lifter rotation.
Check your rocker geometry real close----make sure the rocker sweep across the valve tip is centered and as short a sweep as possible.
Finally, use inner springs to break in the cam/lifter.
WOW! Thanks for that info. I was thinking 150# on the seat but you say 180# is OK? I know the "battleship" spring was over 150#, so that makes sense. You say break-in with ONLY the INNERS or do you mean WITHOUT the inners, OR with both the inners AND outers? No excessive wear with 400#+ open? That sounds good. The heads I'll be running are similar to the Edelbrocks (which they are patterned after) and don't stall within the range I'm looking at, they're still climbing, albeit slowly, at .750", so I figured .650ish at the valve would be good. Hopefully the longer stroke and increased CID will help reduce the top rpm to 7,000 or less, especially with the smaller .654" unit.
Yeah Lunati makes some killer stuff that they don't market, like the MaxWedge StageIII cheater cam I have. 268/272*@.050" with .518" lift, 105LSA. The lobes are SQUARE looking and have awesome area-under-the-curve (valvespring KILLERS!), but really work mild IRON heads in a 440. I did not know they made mushrooms, though. What kind of specs or do you have any info on them? I had a REED cams catalog with maybe 2 dozen lobe profiles (.960 and 1.0" min-dia. profiles), but I think REED went belly-up like CraneCams 
RB 
Posted By: cbarracuda
Re: Mushroom Tappet Cams - 03/22/10 04:00 AM
Yeah, you're right. The cam will go on the motor with plenty of room without back spot facing, but if you over rev the engine then you will probably break the bottom of the mushroom lifter. To prevent this you should back spotface the bottom of the lifter bore. All it does is provide a smooth , flat surface thats perpendicular to the tappet centerline so it will hit squarely when you float it and not brake off a corner
Posted By: Bighead440
Re: Mushroom Tappet Cams - 03/22/10 04:01 AM
Quote:
The mushroom cam with a 654 lift and a 316 duration is a different cam from what Mopar calls the mini express with 690 lift and a 328 duration. I was using the small mushroom because my car wieghts 3700 lbs with my in it, It was a 68 charger that ran 10.50s. The mushroom cam that I found in this forum had 630 lift with 1.5 rockers and it will have 652 with the 1.6 that I have on my small block. the only marks on the cam are mv102
Not arguing, but my .654" says "MiniExpress" right on the BOX!!! It's weird! Maybe you're SB cam is a STX-60 like my BB one, or a knock-off of it. It's 271@.050 and .632" lift, so that would be close. good luck with it, regardless!!! 
RB
Posted By: 40ford
Re: Mushroom Tappet Cams - 03/22/10 12:01 PM
To try to answer some of your questions----
The engine we built(about 20 years ago) was a 451, with serious 915 heads---later replaced with serious stage VI heads(flowed slightly over 300CFM @.600"), compression was 14 to 1, Dominator carb, etc. The engine really came alive above 7000----
I seem to remember using the inner springs only to break in the cam/lifters---but my memory may be poor.
Lunati used to offer mushroom profiles patterned after their NASCAR grinds of the late 70s. I suspect they will still grind a mushroom grind---after all they want sales too! The cam I specifically remember had .635" gross lift, 5-6 degrees more duration than the Mopar .690" cam. The cam was easier on springs than the Mopar grinds. I do remember using Isky springs---they worked better and lasted longer in our oval track application.
The Mopar mushroom cams came out of the NASCAR big block era and were originally ground by Cam Kraft. They used battleship springs. And the cam/lifters/ springs lasted one race. A lot of cam wear/ spring breakage occurred. I would not use the battleship springs----there has been a lot of improved technology in springs in the last 20 years.
Posted By: atoetly
Re: Mushroom Tappet Cams - 03/22/10 12:47 PM
Quote:
Quote:
The stx 42's have more duration @.050 (290) than the stx 62 (280) but the 42's have less lift 673 with 1.6 rockers. The stx 62 has 687 lift with 1.6 rockers. My first stx 42 had a lsa of 108 and my current one has a lsa of 110 don't sound like much but it gained me piston to valve clearance and also mellowed out the idle.
OK, I see, the STX-42 wasn't on the RacerBrown sheet I have. The 62 sounds similar to the "MiniExpress" that I have (314deg x.654" MoPar), but mine is on a 107deg LSA according to (erratic) MoPar. What did the 108LSA STX-42 idle at, 1200rpm??? What did you run for valvespring? I have some in mind... RB
Idled best around 1500 And for valve springs? I'm running an all composite mushroom lifter that was made by schubeck thus the huge radius at the bottom. My springs are a comp spring p/n 932 with an installed height of 2inchs it gives me 200lbs seat and 510 over the nose. SM will make a set of mushroom lifters and from what I hear he will make them with either a composite face or all composite but then there is that cost issue.
Posted By: cbarracuda
Re: Mushroom Tappet Cams - 03/22/10 02:29 PM
mopar conection have new lifters
Posted By: polyspheric
Re: Mushroom Tappet Cams - 03/22/10 03:17 PM
the huge radius at the bottom
You're confusing me (fairly easy to do).
Do you mean at the body/base intersect (below the tappet gallery bottom), or at the contact surface?
Posted By: Steve1118
Re: Mushroom Tappet Cams - 03/22/10 03:24 PM
The mushroom deal was actually developed for the NASCAR program....Chrysler wanted the big numbers, and they were not feasable with a flat tappet. Rollers were illegal in NASCAR....hence the develpment of the mushroom tappet. Those old "mini express" worked real good, too.
Posted By: atoetly
Re: Mushroom Tappet Cams - 03/22/10 04:11 PM
Quote:
the huge radius at the bottom
You're confusing me (fairly easy to do).
Do you mean at the body/base intersect (below the tappet gallery bottom), or at the contact surface?
The radius is where it transitions from from main body into the 1 inch portion of the lifter. Not where it rides on the cam.
Posted By: polyspheric
Re: Mushroom Tappet Cams - 03/22/10 10:50 PM
Thanks, that makes more sense.
BTW: there are really big radius flat tappets for other engines: 3".
Posted By: DBCooper
Re: Mushroom Tappet Cams - 01/13/17 10:42 PM
Anyone have a mushroom tappet Mini Express cam that they would like to sell ?
Help a brother out Please
Posted By: Porter67
Re: Mushroom Tappet Cams - 01/13/17 10:58 PM
Set your ebay preferences to email you when a mushroom cam/lifters come up...
Last week one seller had a non dc but mopar cam like the mini ex for $250
He had a set of dc lifters and one other brand at $200 a set.
I cant find the listing so they must have sold, but they do pop up there every few months.
The cam was like .640 lift, as cool as it was ive got near the same cam specs in a hughes so I passed.
Posted By: DBCooper
Re: Mushroom Tappet Cams - 01/13/17 11:01 PM
Thank you EV2Bird
Posted By: Monte_Smith
Re: Mushroom Tappet Cams - 01/13/17 11:41 PM
I don't think some understand the purpose of the mushroom tappet. First, it is not mushroom shaped at all. It just looks like a regular lifter with a 1" diameter base welded on it. So it's flat on the bottom and is STILL a flat tappet lifter and as such is limited on spring pressure just like any other flat tappet. It provides no more lift. The ONLY things it does is move the valve events. Meaning the lifter starts up the ramp and comes down the ramp at different times because the diameter is larger. The larger diameter means it contacts the ramp earlier. That's ALL, nothing else. Why was this needed? Because at the time, cam cores were very limited as to the valve events that could be ground into them. So you fixed that with a larger lifter. With cores available today, the mushroom lifter is NOT needed. You can get cores to get about any events you want within reason
If you look at the drawing linked to above, it shows exactly what I am explaining. But you can also accomplish the same thing with a cam with more of a roller profile on the lobe.......or just put 1" lifters in the motor.
With the roller profiles available today and everything we have to choose from, it baffles me though why guys even WANT a flat tappet though. Just as David Reher addressed in that article, there are so many potential issues with a flat tappet
Posted By: DrCharles
Re: Mushroom Tappet Cams - 01/14/17 03:14 AM
With the roller profiles available today and everything we have to choose from, it baffles me though why guys even WANT a flat tappet though. Just as David Reher addressed in that article, there are so many potential issues with a flat tappet
At a given maximum lifter acceleration, you can get more lift out of a 1.00" tappet than you can with a .904". My refaced Mini-Express is .652 gross lift (.018 lash), 272@.050. I feel safer running it on a 1" lifter than an Ultradyne .640 on a .904, which is 277@.050. The mushroom has more lift with less duration. Sounds kind of like a roller...
There are also potential issues with roller lifters on the street... depends on who you talk to. Like everything else here, there are multiple opinions.
Perhaps more importantly, not all of us have John Force's budget for engines and components. A good set of roller lifters alone costs more than I have in my mushroom cam & lifters, pushrods, used Isky rockers, and Comp springs
Posted By: Porter67
Re: Mushroom Tappet Cams - 01/14/17 03:24 AM
I would think if they were the end all of camshaft/lifter designs they would still be made today.
Its easy to fully understand the budget! At times we do, only what we can do which is better then nothing.
The shubeck puck solids at 69 grams and $700 might seem like alot of money upfront, I just sold a set I used on six cams over a five year period with zero issues for $350.
In those six different cams at $150X6 a set of regular lifters Im far ahead of the lifter game.
As well Ive resold the cams, cheap but they would still rotate a new set of lifters.
I really wanted the cam/lifters I mentioned off ebay but I just didnt have a reason.
As far a solid roller lifters, for the street if you can find a old reed cast core roller and matched lifters you can run a gentle roller cam for a long time.
Or if like some on here that god blesses you everyday, you can run a normal roller cam and lifters.
Posted By: madscientist
Re: Mushroom Tappet Cams - 01/14/17 03:44 AM
One of the issues I have is that the valve gear on OE heads just isn't rigid enough for the spring pressures a roller needs. If all you are doing is beat the hell out of the valve gear you aren't doing much.
That's why I used a SFT in my last build. When I do the W-2 heads I may use a roller. Or, I may say piss on it and use a mushroom lifter.
Like I said, I have the lift I wanted with a .904 lifter or I'd have used a mushroom this this time. But much over .600 lift and it's hard to get all the valve train correct.
Posted By: Porter67
Re: Mushroom Tappet Cams - 01/14/17 05:57 AM
Back to back is there really any positive benefit of running the old cam and lifters? Other then just the want?
My last hughes solid I was at .680 lift at the valve and with there vast selection of cams going up the ladder in duration I could stay near .700 lift with a 260@50 or what is it the 276@50 or in between.
Reed used to be able to grind them up till maybe ten years ago or so, but I just looked and if they moved out of GA, there done, history.