Indy SR's

Last year I reworked a set of older Indy SR's.
These were probably about 1998 vintage or so. The early ones had more of a "D" shaped chamber. The newer ones have the heart shaped chamber.
The newer chamber is cast with more space around the valve adjacent to the chamber wall.
The early ones had noticeably weaker low/mid-lift flow with the valves being more shrouded by the chambers.

I have only a couple pics, and not any good pics of the complete OOTB chamber shape.

The early heads also had quite a bit more meat that needed to be cut out of the bowls, as well as having a pretty chunky guide boss.

They can end up as good as the newer version, it just take more work to get them there.

The first pic is after the valve seats were cut along with a chamber relief cut.
You can see the extra material under the seat and the guide boss that will be getting trimmed away.

The ootb flow numbers aren't really that good at all, and aren't any better than a half way decent ported 906 until over .550 lift, and the low/mid-lift flow is way down compared to even a mild bowl blended stock head.

These are the kinds of heads where if you just ran them ootb, you were likely going to be disappointed.

Tested on a 4.375 bore, 28" pressure, radius plate on intake.
OOTB test is std port, ported test is MW size opening.

A- OOTB
B- ported

Intake:
Lift------A/B
.100---69.0/73.1
.200--124.9/146.4
.300--173.2/209.8
.400--218.0/260.8
.500--255.9/310.7
.550--268.3/326.9
.600--274.8/336.4
.650--278.5/342.0
.700--281.6/347.7
.750--283.5/353.4
.800--284.2/359.1

Exhaust:
Lift------A/B
.100---52.8/ 57.2
.200-- 89.2/111.6
.300--127.7/162.4
.400--162.4/205.8
.500--187.2/236.8
.550--196.7/248.3
.600--203.2/252.1
.650--206.2/256.7
.700--208.1/261.6
.750--210.8/266.2
.800--212.7/268.1

They look like they clean up real well. Thanks for the pics.

Very nice gains for sure. These seem to be the forgotten head out there anymore these days. I have always seem a fan for a nice streetcar and don't understand why they get overlooked so much.

Nice work, no doubt. The last bench testing I did on 'low floor' ports I found the area in the chamber along the shortside radius was pretty sensitive because it is a continuation of the shortside. I would be curious how much flow would be affected (negatively) if you milled the chambers to the intake seats. I believe the middle peak between the valves ADDS flow when done correctly so, i would think the newest casting would be capable of higher cfm. However, that area appeared less 'sensitive' than optimizing the chamber wall side transition form the valve seat.

Chad Spier, over on The Bullet, has some nice low-port SBC models that i feel are worth viewing, particularly on the guide tail and floor shapes.

Very nice! Those numbers are pretty close to what mine were from Modern many years ago. I just went 8.99 @ 150 in my 3480lb barge so they can make half decent power with a whiff of spray.

You're right, OOTB, pre MW porting they DID NOT set the world afire!

Sean, SR's aren't low floor heads.
They have the tallest sort turn of any of the Indy heads I've seen.
Way taller than a -1.

I agree that the newer chambers with the added material between the valves should be "better", but it doesn't seem to make much difference in the "big number" on these things....... At least with what I'm doing.
If you're looking for 360-370, it might be more of a player.

Get the short turn right, pinch opened up enough, bowl/guide boss area sized right, clean up the rest of the port...... Mid-350's@.700+ are usually the norm at MW size.

Al, I think it just comes down to cost.
Even the newest SR's require more work than their competition to get them past the "disappointment" stage....... And time is $$$, and the heads aren't bargain priced to begin with.

EZ's have much more user friendly intake ports(less work to get decent flow), and they don't need special headers or the external oiling lines(I actually prefer the external lines myself), and they're a little less $$.

The TF heads have really changed the game for the average guy looking for a 550-700hp BB Mopar build. You just can't touch anything else at that price point that gives the same bang for the buck.

I'm just curious. Why the preference for external oil lines?

I love seeing this kind of post, BTW!

I love seeing this kind of post, BTW! [/quote]

Yes, I agree.

Thank you for taking the time to post these types of things Dwayne!

It's full time oiling, and restrictors are easily changed if you want to increase/decrease the flow to the top end....... Without resorting to either a grooved #4 cam journal or bearing...... Both of which take oil away from the #4 main.

I look at the external lines that are used on some Indy heads as an item in the "pros" column.

Cost considerations aside, I think it would make for an interesting test to compare some TF240's against some similarly flowing std port SR's on a 700hp-ish 505 or 511.
The SR's have such differently shaped intake ports than the TF, along with a raised, better flowing exhaust port........I'd love to see how that would play out.
Would it make any real difference or not?

quote]

Cost considerations aside, I think it would make for an interesting test to compare some TF240's against some similarly flowing std port SR's on a 700hp-ish 505 or 511.
The SR's have such differently shaped intake ports than the TF, along with a raised, better flowing exhaust port........I'd love to see how that would play out.
Would it make any real difference or not? [/quote]That would be a comparison that I would be very interested in also, I am pretty happy with my ootb 240's, a before and after porting comparison would be some very interesting info also.

I've got OOTB SRs on my 440. The numbers you posted make me think that it may be time to get some work done on them.

If they are the "newer" ones with the heart shaped chambers, the OOTB low/mid-lift numbers are a little better.

I brought this up from the "Best of Moparts" forum:

440-SR head: 4.375 bore, 28" test pressure, radius plate on intake, no flow tube on exhaust.

Intake ports;
A- OOTB std port, zero porting
B- OOTB CNC Maxx port. this is an option from Indy where they CNC the intake opening to MW size, along with doing a CNC bowl blend. no additional porting or valve seat work.
C- this is how i like to prep these heads, so you get the benefit of stepping up from a stock head or RPM type head.
this particular port started out as the CNC Maxx job, then got the chambers ported, my valve job, back cut valves, "bowl ported", guides streamlined, short turns reworked.

lift----A----B----C
.100--70.7/ 71.9/ 74.7
.200-134.2/131.7/147.6
.300-195.2/189.1/212.0
.400-238.2/239.3/265.1
.500-263.6/284.9/305.1
.550-275.6/302.9/319.7
.600-279.3/286.1/329.4
.650-280.3/286.8/336.6
.700-282.3/286.1/343.3

Exhaust ports;

D- OOTB std head, zero porting
E- OOTB Maxx head, CNC bowl blend
F- Maxx head, PRH valve job, back cut, mild full port and polish. this is how i like to do these to match the intake port in column "C".

lift----D----E----F
.100--56.5/ 54.7/ 56.9
.200-104.1/ 95.4/131.4
.300-142.6/131.4/157.2
.400-171.1/159.9/197.1
.500-195.9/182.9/225.9
.550-203.3/192.4/236.2
.600-209.5/200.7/245.3
.650-214.5/205.7/253.3
.700-218.2/210.3/255.6


These heads will flow 320+ by .600 lift while retaining the std port opening with a good valve job, bowl work, chamber clean up, guide trimming, and cleaning up the pushrod pinch.

4.500 Bore x 4.150 stroke. Great torque. Always left and 60ft. The best leaving @3200. Best e.t. 9.77@139 3390lb. with driver.

The raised exhaust port position means header choices can be problematic, depending on the chassis they are going into. Back in the day they were a decent head and you just had to deal with the header issues, but with so many standard exhaust port position heads out there now, which would you choose - the SRs that might require a custom header or something else? Been sitting on a set for a few years waiting to go into an a body, but am contemplating the trick flows because of the header availability and relative OOTB ability of them.

Like fast said, more than enough to break my oldiron block

I am curious as to how much improvement can be had with port work on the 240's, I am sure the SR's will out perform them but by how much,and is there enough gain to be had with the 240's to make it worth the expense.

Is there any work to be done on the SR CNC295’s or are they already at max effort?

Those out of the box numbers look familiar.

Well I don't consider the header issue a big deal. There are some OOTB ones available and if you are doing a low deck there is no issue at all. I prefer to look at potential of a given part rather than ease of use or ultimate cost. Lord knows I am not an Indy fan per se but have used their stuff for sure.

I have not looked at seen or touched an SR head in a long time, so cost is not something I have looked at either. To me the potential would be the ultimate factor. Even if building a tall deck for an A body, can get headers made anywhere, and they will be superior to anything from a box. I have not done anything other than look at a TF head. Will see soon though as a friend who is an engine builder in Canada I think might be using them in an upcoming build. Be interesting to see what he manages to get from them. I understand the appeal of "budget friendly" heads that can just be bolted on using existing pieces as well. Budget is always a concern on some level.

Just don't hear much about the SR heads anymore. I had a set back in 2000 that we used on my 65 Belvedere. Just a little 451 pump gas deal in a street car. Std port window M1 intake small solid tappet cam, zero maintenance ice cream fetcher. Used to drive it to the track and when I moved to San Antonio it was my daily driver as well. It ran 10.50's that way at 3600+ lbs. on pump swill. Was a 47 mile one way trip to San Antonio raceway for me. Had a lot of fun with it for sure. First time I took it to Sonoma Raceway when I got back to California I ended up selling it as a nice gentleman was not letting me go home with it

I have always really liked the SR head, but like Dwayne says, its becoming hard to justify. This car has Sr's 505" bracket car, 8.70's, these have been on 3 cars now flawlessly....lol...and will most likely end up on a forth next year.

My early SR's were livened up years ago by the talents of Nick at Compu-flow and as a standard port window made some decent power.
BEST machine later on advised me that if a Max window and port were to be introduced, it would be a whole other world, but I stubbornly stayed in my ballpark till this day because I wanted to keep a small window and see what decent torque it could still muster in the lower lifts. Since then, the technology has changed for the best of both worlds and I guess I have to come up to speed literally.

I street drive, so low lifts is where it lives most of the time.

I'd think Trick Flow 240 heads would work for you given your focus on a standard port window and your focus on weight.

Hhhhhhhmmmmmmmm. Thank you.
I gather those TF's have a better flow at the lower end while utilizing a stock window. I must admit, I have not looked so much into them.
Yes, in my case, I figured that the weight or lack of it would not be asking too much of the engines breath to achieve a decent power level in keeping with a small tire on leafs.

Great info as I also enjoy reading post like this and learning how certain heads perform. Thanks Dwayne for posting this. Ron

Yes, not a cost prohibitive/ chase every cfm available effort. But definitely a major bang for the buck.

I quoted these separate, to ensure you know I am coming from a high-level of respect of your abilities. But, when I say 'low floor' I mean it still runs uphill to the shortside. Or, if there were enough material to raise the floor and the roof proportionally without increasing cross-section, flow would increase.

Got it.

I'm actually working on a set of SR's now that were originally done by Nick at Compu-Flow.
This customer has been running these for a number of years, and they seemed to be holding up quite well.
They were due for a freshen up so he sent them to me and asked to look them over and see if maybe I could get a few more cfm out of them.
Nick did a nice job, but it did seem like I could go after a couple of areas that might yield a little more flow.
The exhaust ports were working pretty good already, so my goal there was to just touch up the valve job and not lose any flow.

For the intake side i went with a different valve job, opened the pinch by .050, trimmed the guide boss more, and just tweaked the short turn a tiny bit.

4.375 bore, 28" test pressure, MW radius plate, same port before & after
Intake:
A- as Rec'd
B- PRH rework

Lift------A/B
.100---70.2/ 72.5
.200--142.8/153.6
.300--206.8/217.1
.400--265.5/270.0
.500--308.5/314.1
.550--321.6/326.1
.600--329.8/338.4
.650--336.6/349.6
.700--338.4/354.1
.750--340.3/355.3
.800--342.9/357.1

Exhaust:
Lift------A/B
.100---56.1/ 58.6
.200--122.0/114.6
.300--151.2/151.2
.400--185.4/185.9
.500--218.3/218.3
.550--231.3/232.4
.600--240.0/240.0
.650--249.4/252.1
.700--257.0/257.7
.750--262.7/264.6
.800--267.2/268.3

Nice improvement Dwayne.
IIRC on my exhaust side that Nick worked, it was pulling 236 and change @600 lift.

If I hadn't jumped head-first (pun intended) into "Victor Land", I could see myself running SRs.

My M.W. non CNC ported SR heads where way better performing than my M.W. ported to the valve seat M.W. Eddy Victors are

Maybe you had the wrong person port them.

the Victors where done before I bought them from the guy I bought them from Same thing on buying the used SR and several sets of used 440-1
Be careful of what you buy used , especially unseen maybe
BTW, flow sheets and head flow from different head porters are not all the same when compared on another bench, huh

They're a little labor intensive compared to some of the other stuff out there(to really make them "nice")......but all in all they're still one of my favorite heads for the BB Mopar.

I have had the SR's on my Cuda for the last 20 years, actually purchased thru World Products, when I worked at the speed shop here, had them ported, and he said they flowed 325cfm at .650 lift, Indy claimed .350 at the time, but that was at .800 lift, and Ken Lazzari said we were on the money with my set.
My car presently has a 493, SR's, .601/.608 solid roller, 10.5 compression, 950HP, 2" headers, Indy single plane, car weighs over 3800lbs, runs mid-10s footbraking. I feel there's more in it, but the convertor is really tight, and I am not a great tuner, may want a 1050 as well.

100%I love reading this kind of stuff.