[chiphead]

If I had another $1500 to throw at it, I'd be changing those pistons and rods first. The shortblock is the heart of the whole project. The heads can be replaced later. The engine could be run as-is, it just won't be a world beater. Path forward depends on the HP and durability needed to put a smile on the OP's face.

It's a bad deal, having to do stuff 2 and 3 times to get it right. If I had all the money back from shops that screwed me over the last 30 years, I could afford to buy a Butler crate engine. Its the cost of being an experienced car guy, unfortunately. Fool me once type of deal.

[steve25]

Even with that Cam I would not put heads on top of those pistons that flow any more then stock.

To me like making 350 hp is all I would ask those pistons to withstand , and stock iron D port heads can get you there easy.

So don’t be looking for anything more then a 9 to 1 compression with what you might be changing , and then with a decent tune you will be safe .

[chiphead]

Yup, its HP level and durability, they go hand in hand when using stock replacement type parts. A 9:1 400 will make decent power, and have a wide enough tuning window to find a tuning mistake before it causes damage. Those pistons around 10:1 would be land mines. A sharp tune at 10:1 with a bad tank of gas, and it's bye-bye ring lands.

[NeighborsComplaint]

I am assuming the builder dyno's it. He was probably relieved he had an excuse for it not running right and you're lucky it made it through the break-in. You got what amounts to an '80's backyard rebuild. It's obvious from the rust and calcium buildup in the head's water passage that the heads were never cleaned and tanked. The block probably wasn't either. The cast "rebuilder special" pistons and the mismatched replacement valves support the minimum rebuild effort and maximum profit scenario. For $8K, you got a lot less than you paid for.

I feel for you and can't really offer any advice than take it to a competent engine builder and go through everything that was done and not done.

Here's a link to complete 455 motors by Len Williams Machine in OK. %8195 buys a fully machined 455 performance long-block using quality parts including block and 6X heads. Spurge with $300 more and you get forged Eagle crank and rods.

http://lenwilliamsautomachine.com/455_Long_Block.html

The logistics of getting an engine from OK to SC aside, it shows you what your money should have bought. Given you already had a complete motor, the magnitude of your misfortune should be even more obvious.

[ponjohn]

With those heads and head gasket, you're lucky if it is 8.25-1 compression. Need 1.5 more points.

[SRR]

Originally Posted by TinRabbit

After a phone call to a buddy pulled one cylinder head and started taking measurements. Double relief pistons that are .020 down in the cyl.
Looks like 1 of the water jackets in the head is plugged with a very old mess.
That .065 head gasket crushed down to approx .045
He recommended to just stick with the shortblock I have for now and he'll help redo topside.

I would think for that kind of cash spent they would have at least did a clean up mill of the heads and block.

[TinRabbit]

Quick update after alot of reading, checking out threads on others builds and looking over what I have sitting on the bench. I still look at the carb they rebuilt (but appears it was just new gaskets, not good clean or shaft bushings) and I can't believe they overlooked that linkage, was so easy to adjust with needle nose pliers. Builder and I have talked about the camshaft, he is willing to refund the cost of the cam since it was not what we discussed during the initial sit down.
Those #96 heads have already a good penny into them with 8 new ex seats, 2 intake valves replaced while the others were ground and the heads surfaced.
Someone who was lurking in the threads has reached out to help with some ideas and their experience over the phone so I'll give em a call to listen and more likely learn.
Took it in the shorts on this one, won't be using the builder again which is a shame because for almost 25 years ive used him for machine work and a few complete builds that worked out great.
Again, thanks, can't say it enough!

[Jay S]

Originally Posted by TinRabbit

Quick update after alot of reading, checking out threads on others builds and looking over what I have sitting on the bench. I still look at the carb they rebuilt (but appears it was just new gaskets, not good clean or shaft bushings) and I can't believe they overlooked that linkage, was so easy to adjust with needle nose pliers. Builder and I have talked about the camshaft, he is willing to refund the cost of the cam since it was not what we discussed during the initial sit down.
Those #96 heads have already a good penny into them with 8 new ex seats, 2 intake valves replaced while the others were ground and the heads surfaced.
Someone who was lurking in the threads has reached out to help with some ideas and their experience over the phone so I'll give em a call to listen and more likely learn.
Took it in the shorts on this one, won't be using the builder again which is a shame because for almost 25 years ive used him for machine work and a few complete builds that worked out great.
Again, thanks, can't say it enough!

Why are you returning the cam? I am a Bullet cam guy. Do you know what it is? Read me the number on back end of the cam.

The over all incompetence of the builder choosing new parts for this was pretty staggering. If you are using a roller cam you always replace the factory valves with one piece stainless valves. The OEM valves are 2 peice and can break the head off valve and drop it into the engine, and the chances of that happening multiply exponentially with a roller cam and used valves. The exhaust might be ok, the intakes have to go. I don’t see that it has seat inserts installed on the exhausts? Would need to see a picture with an exhaust valve to tell for sure. The blue residue on the head surface suggests it had a standard Permatorque Felpro head gaskets on it, they measure .045” on the shelf a crush to around .039”. I have no idea why the builder said it has a .065”?

Pull those crappy 8VR bevel top pistons out and at least install a factory style Speedpro L2262F forged pistons. They are only about $400 and it is the same style piston it had from the factory, the balancing will be closer to OEM specs, the compression will be raised nearly a point from what is in it now. They are what the builder should have used in the first place.

[P@blo]

I would start the process of reviewing what you paid for and what work was actually completed. The builder carries some responsibility unless you gave him a signed cheque and provided no direction. I find it odd he is quick refund the cam if there were no problems. Ask him to refund the pistons too...

Any way to post the actual build sheet? New SS one piece valves are $250 minus the labour you were paying to work on salvaged two piece valves. Hopefully solid bronze guides and not cheap liners were installed too.

[steve25]

Look around, maybe you can turn up a set of 6X-4 heads already done with there 89 CCs and then sell your 96 heads .

A lot of folks are still looking for those 71 castings with it 96 Cc chambers.

[srmmmm]

Originally Posted by Jay S

If you are using a roller cam you always replace the factory valves with one piece stainless valves. The OEM valves are 2 peice and can break the head off valve and drop it into the engine, and the chances of that happening multiply exponentially with a roller cam and used valves. The exhaust might be ok, the intakes have to go.

My engine builder said the original valves in the 6X-4 heads I used were in excellent shape. A Comp XE276HR cam was installed with 1.5 rockers (.502/.510), new springs and retainers. Spring seats were all milled for correct spring heights. Do you think I should be concerned about the valves?

Rest of the build: 350 block bored .060 over, Eagle 4.25" crank, Eagle H-beam rods, Ross flat top pistons set at 0.0, CR 9.3

442Lb Ft@4300 and 453HP@5600

[steve25]

If my seat pressure with a HR Cam was over 150 then I would sleep better with new aftermarket one piece valves.

Plus they can be had with under cut stems, so a long with the added safety you can pick up some air flow.

[Dragncar]

Originally Posted by srmmmm

My engine builder said the original valves in the 6X-4 heads I used were in excellent shape. A Comp XE276HR cam was installed with 1.5 rockers (.502/.510), new springs and retainers. Spring seats were all milled for correct spring heights. Do you think I should be concerned about the valves?

Rest of the build: 350 block bored .060 over, Eagle 4.25" crank, Eagle H-beam rods, Ross flat top pistons set at 0.0, CR 9.3

442Lb Ft@4300 and 453HP@5600

It would not have crossed my mind to use OEM valves. What does it even matter that the builder said the valves were in "excellent shape". What it means is, he does not really know Pontiacs.
Stock valves are the biggest no no in the Pontiac world. Even more than making real power with OEM cast rods.
I am a welder, all welds are actually some sort of a flaw in steel . One piece forging are much better.

[unruhjonny]

OK, I might get some flack here..

Wouldn't exchanging 71-96 heads for 6X-4 be a horizontal move?
71 #96 heads = 96cc 2.11/1.77 valves
6X-4 heads = 94cc 2.11/1.66 valves

I have understood that the 6X-4 is a "fan-favorite" because they can be modified to accommodate the 1.77 exhaust valve, and are better suited to porting than the 71-96 heads.

I think the post pointing out those two combustion chambers had different valves (both exhaust, and both intake valves are obviously different) was an astute observation.

If the short block is going to be torn down to install better slugs, decking the block just to make it true would be a good move (if any honing ect is going to be done, I'd think it would need to get re-cleaned, so a decking doesn't add any extra work.

If the heads are to be retained, maybe the valves and installed spring pressure ect need be reviewed?
I personally would have insisted on all new valves...
Maybe the head can be measured and milled to ensure you're not having too large a combustion chamber (if the valves are inconsistent, it's quite plausible that each chamber has different volume).

If the deck and heads can be made true, then cometic gaskets would be a viable option.

In my opinion the 71-#96 heads are a good casting.

Just spit-balling here...

[srmmmm]

Originally Posted by Dragncar

It would not have crossed my mind to use OEM valves. What does it even matter that the builder said the valves were in "excellent shape". What it means is, he does not really know Pontiacs.
Stock valves are the biggest no no in the Pontiac world. Even more than making real power with OEM cast rods.
I am a welder, all welds are actually some sort of a flaw in steel . One piece forging are much better.

Builder was Len Williams....He put a lot of time into the valve train geometry with the spring seat milling and custom length push rods. I had even asked if the valves needed to be replaced.

[unruhjonny]

I will add, that if a Pontiac builder/company was to create better thinner compression height head gaskets, I'd be on board to buy several sets.

Finding head gaskets which have a smaller compressed height than the standard FP gaskets are few and far between...
I might have an idea about this because I've spent a LOT of time looking for them...

[b-man]

#96 heads are great.

But not for a performance 400 build, and the 6X-4 heads aren’t right either.

Both have too much combustion chamber volume.

Period.

If you absolutely must use iron heads then go with a ‘68 -‘70 350 head (#17, 47 & 11) and convert them to bigger valves and screw-in studs. Another would be 1969 #46 400/428 heads. Small enough chambers to get mid-9:1 compression numbers, most will be somewhere between 75 and 82ccs.

[steve25]

Here’s a comparison dyno test of a 455 done by Pete McCarthy back in 92.

It’s a strictly done comparison between the # 96 casting and the 6x with its smaller 1.66” exh valve .
Up to about 5200 rpm the 6X is better.

Both sets of heads where set up for the same compression ratio.

If they worked good on a 455 then the same results would take place on a 400 cid motor used in even up to 5400 or 5500 rpm.

The 700 cfm Holley used was set up by Brad Urban in Ca.

He knew his stuff, I wish he was still with us. :-(

[TinRabbit]

[QUOTE=Jay S;6613870]Why are you returning the cam?

No return on the cam, a refund so a lil $$ in the bank to plan what to do with the shortblock.