Ron, I agree 100%! Reminds me back in the mid-70's when I was doing a lot of street-racing with my modified 13second 340 Duster! A couple of the Chevy guys from the old neighborhood were gonna "clean my clock"!!! One had a 350 4-speed Nova,and the other,a 396 4-speed Nova. Both had basic modifications,similar to my car. Neither one could beat me in a best 3 out of 3! Won all 6 races! THEY WERE PISSED! NEVER bad-mouthed me again! RandyB

heres a couple of statements i'd agree with:

Quote:

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On the other hand, if everything is working right even if a little worn, I wouldn't expect big performance gains for quality work and new parts. Something has to be wrong first, and then fixed, to see the gains.

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and i think the jist of what Ron is saying here gets overlooked way too often:

Quote:

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I know that this post by Fast68 makes you realize how important the little things are. He is the best at it and I know from my years of Mopars if you just stick to the basics and do that right you can have a good running combo. Its not as much rocket science as some think but doing the simple basic things right to get the most out of a simple combo.

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i remembered to bring the camera home....some of the pics came out okay.

here's a shot of the intake seat as i rec'd the heads, after i had wiped the 2 coats of Dykem off.

exhaust seat....

here's a nice touch.....
several of the guide bosses were broken away at the port end.
i think i figured out why they had machined the entire guide boss from the topside of the heads.

i normally drill and ream for new guides from the bottom.
these were done from the topside, down.
on many guide and seat machines, there isnt enough clearance with the head sitting in the machine right-side-up to get a core drill into the guide.
the guide boss gets broken when you are aggressively feeding the drill through the head, and break through the other side too quickly.
since the bottom of the guide bosses are chipped/broken.....the drilling operation was done from the top>down, and the top of the guide bosses were removed to allow enough room to facilitate getting the drill into the guide.

another possibility is they were done on a milling machine, and they didnt have a roll-over fixture, and just had the head clamped to the table.

in any case....with a lighter touch during the final 100 thou or so of the drilling operation....you can avoid breaking the guide bosses like this......

those are just ugly!

i tried several shots of this, but it just didnt come out very clearly.

this is a shot of the intake seat after i had kissed it with a stone.
you can barely see the area of contact in the picture.
its from 12 o'clock to about 5 o'clock.

this is the same deal on the exhaust, although its pretty blurry.
its the shiney area from 12 o'clock to 3 o'clock.

this is after 2-3 solid hits with a stone. the first hit barely touched on one side.

you can really see the chatter from the seat cutting operation in this pic, from about 6 o'clock to 9 o'clock.

this is after i bead blasted the heads, replaced the guides, and recut the seats, bowls, chambers.

and this is the final product after blending the bowls and bullit nosing the guides a bit.

what you cant see is that i actually knocked the intake short turns back a fair amount.

as you can see.....nothing fancy at all, but it made a huge difference in flow.

Dwayne,

at what point do you hit the cutoff and say these can't be fixed, or are not worth fixing? is it easier to start with a fresh unscrewed set of heads before continuing?

FAst what kind of pilots do you use tappered or straight? Those seat look alot better now thats for sure

Dwayne, the craftsmanship and pride in one's work. Is quite evident in those pictures. Kudo's to you for enlightening some of us who have never seen the difference. Or worse still those who have experienced the difference but didn't know what was wrong. Jim

Dwayne,Thanks for the info and pics! Very enlightening RandyB

I still remember the guy at 75-80 w/ the pretty 383 Runner that had a .509" cam, some off-brand 10" converter, 3.55s (at most), etc. He had his hopes up thinking he was going to bust into the 12s, only to see them completely deflated w/ mid-to-high 15-second ETs. I could tell from chatting w/ him briefly that he didn't want to hear anything about how his combination was just plain wrong, either.

Thanks for posting Dwayne ......When I'd picked this car up out of California for a customer, the guy in California had plans of putting it together like that since he'd had the work done......I don't trust hardly anyone's work, so that's why I shipped them to you.......Like a good friend of mine always says; "If you always pay for the best, you'll never have anything to complain about."

Unlike a lot of restoration shops, I care that the cars I do at least run respectably, which in my mind would be at least 105MPH in this A-body, if it were ever ran at the strip......at least, that's what I think these cars are all about.......

So what causes the runout (is that what it's called) on the reconditioned valve seats? Is it a bent mandrel guide that is in the valve guide or one that's too small and is wobbling or tilted?

it can be a bent or worn pilot, the wrong sized pilot, or just poor machining practices by the person performing the work.
depending on the type of equipment used, operator finesse is more or less of a component of the final result.

for instance, if the equipment being used is of the live pilot type, then its pretty much mandatory to level the column to each individual guide before cutting the seat.
the seat cutter and pilot are positively attached to the column, and will cut square to it. if the column isnt exactly square to the guide, you'll get runout.
how much runout depends on how far off the column was in relation to the guide.

if its a "production" type shop using that type of equipment, and they level one guide and then cut all the seats referenced from that one leveling operation....you'll have one seat thats pretty good, and the others can be off a fair amount.

the ball driven seat cutters running on a fixed pilot are somewhat more forgiving to having the column being "dead nuts" square to the guide, since the cutter is riding on the pilot, which is fixed into the guide, and there is some room for misalignment in the ball drive, although its still best to square the column to each guide.

another possibility is the equipment being used isnt really the ideal set-up for machining seats(I.E; a seat cutting system being used with a milling machine isnt all that user friendly), and will require a more skilled operator to achieve consistantly good results.

some types of seat machining equipment is just easier to use than others.

the bottom line is, some shops seem like they are always in a hurry to get the work done.
unfortunately, some operations just require more time be devoted to them if you really want them done "right".

when you combine an unskilled operator(or an operator who just doesnt really care) with equipment thats unforgiving, you're not going to get positive results.

i was going through some pics for another thread, and forgot about this hot set-up in valve sealing technology.
this was a set of heads bought from Ebay, with all new parts, fully ported, and "ready to run".

it would have run okay.....but might have used a wee bit of oil.

for those of you not familiar with this type of seal.....the top half is missing. must be they got stuck in the keeper grooves, and were then forced down over the stem.....which just rips them in half.
there is no "sealing" going on with this arrangement.
its more of a "high lube" seal

the white stuff in the keeper grooves is a thick coat of assembly grease.....cuz those keepers really need to be pre-lubed

This makes me want to go disassemble the heads I bought off eBay years ago.

They were 516's that had been "bowl ported" (which from what I can see/feel down the ports means that a 70 degree cutter was run down there) and had 2.14/1.81" valves installed.

When the heads came, the installed heights are pretty close... within .060" the intakes look sunk down kinda' like the pics on this thread. When I stuck a straightedge across the tops of the valve tips, I thought I was going to

So I never used 'em. Don't want to try to unload them on the next sucker.

BTW, I had a 15 second 383 Valiant. Of course, it might have gone faster with the trunk emptied, the passenger evicted, and the three flat cam lobes I found replaced.

I've always figured that with those changes, it was a mid-14 car. Which would still leave me with that look on my face.

-bill