Custom head gaskets

Mr_Roboto

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Anyone ever do this? If so, who'd you use, how was the quality and what did it cost? Looking for a set of gaskets to bump compression and get quench that's not shit on my Pontiac 350. That means a gasket that's .025 +/-.002. All Felpro makes these days is a .039 gasket. I'm trying to avoid zero decking my block, but may go that route instead. It still leaves me with some ignorantly sized bores.
 

DEEZUZ

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Why are you so God damned difficult. Stop the heritage. Just go LS
 

Mr_Roboto

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Smarter man than I right here folks.
 

Gamble

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Flatout group in Mundelein. He has a waterjet and his business is custom headgaskets
 

Mr_Roboto

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Flatout group in Mundelein. He has a waterjet and his business is custom headgaskets
For all its short comings there is a lot of cool car shit in Illinois. Thanks for the name.
 

Mr_Roboto

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I am going to build the original into something but it has a rod knock. Probably tomahawk rods and some sort of pistons. If I could get 7 inch BBC rods without it costing a fortune I would probably do ls1 pistons.

I have a second one and am planning an install with an mooks T66. I am prepping the carb now and have about a quarter of the header fabricated.
 

ilikemtb999

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I recall a hotrod article where they made like 700hp out of a 350, I know they can be punched out decently but that probably costs an arm and a leg.
 

Mr_Roboto

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I recall a hotrod article where they made like 700hp out of a 350, I know they can be punched out decently but that probably costs an arm and a leg.
Fuck that, I'm going to probably boost the piss out of it. Unless you're dropping $2K on Edelbrock heads you're looking for a few very specific years to get to 9:1 and make decently lackluster power N/A.

At this rate I'll be doing something delusional like moderate to high boost on pump gas because I'm at 7:1 static compression. That said, if I can keep it in my pants rev wise I can probably make it live pretty well on boost. There have been a few cast rod 455s done on Turbo Mustangs with good results (10s in 3700+lb cars.) Since the rods and crank are the same with the block being similar I think she'll take a decent amount of power provided I keep my goals sane. I need to revise my project thread, it lost all its photos when photo bucket puked its guts out. The T66 looks like it will be a pretty good fit.

http://turbocharged.com/catalog/compmaps/images/t66.gif

If you look at where 50lb/min (500ish hp) intersects with a pressure ratio of 2.0, I'm in the 70% island. I can get up to 250ish HP N/A before I cross out of the 65% island. With surge being at 20lb/min at a pressure ratio of 2.0, I could get down to 100hp N/A before hitting surge, although I have my doubts about that. These engines were rated ~250hp gross, and I'm going to have a 4bbl intake instead of a 2 and probably ported heads.

My big concern is the clutch and the manual trans behind it. I think it will probably stick around on lower boost until I destroy the clutch. At that point I'll probably have to figure out if I want to go to the TH400 sitting in the garage.
 

daturbosix

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i have a 74 455 with 4x iron heads. was a runner, was rebuilt. has been sitting in my firebird for like 5 years now..

im considering going LS or BBC if i were to sell it, cuz pontiacs are so god damn expensive to make decent power with.
 

Mr_Roboto

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Find a resto guy for that. A 455 price would mean I would go LS.

That said a dude on turbo mustangs was running 10.70s or so on a Blow through 455 at 15 psi or so. If you want to go na on it I can yank the 96es off my 350. They are 9.5:1 or so on a 455 although small valved. Those 4xes are presumably the big chambered heads. Any more it is likely prudent to use Edelbrock heads and aftermarket con rods.
 

MonzaRacer

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Factory Pontiac arma-cast rods are toothpicks, even a plain old set of Eagle Ibeams double bottom end strength. Pontiac cast cranks are beasts regardless of the bad rap. Add some main studs and head studs, give the heads a deck and make sure intake side is cut appropriate amount also. Pontiacs make ludicrous low end torque with good air flow. Even a good bowl blend, port match and decent sized valve (issue with 350s small bore long stroke substituting 400 block gains many benefits) and proper cam and not getting greedy with duration and lobe center.
Pontiacs were NEVER designed for high RPM till Super Duty design hit. Like a Caddy engine its big, low end torque maker that will accelerate very fast if you play the parts right.
Pontiac rods will fail before cast pistons will!
IF you can locate a set of old #2095 326 heads you can get 10.5+ compression, still flow good and handle mid size valves.
Also dont worry about older Pontiac heads, after having had Pontiacs and building many sets I have yet to see unleaded hurt ANY seat. Just install good bronze guide liners and stainless valves.
Oh and most Pontiac blocks will spit down lifter valley sfter you start eclipsing 600hp!
 

ilikemtb999

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Find a resto guy for that. A 455 price would mean I would go LS.

That said a dude on turbo mustangs was running 10.70s or so on a Blow through 455 at 15 psi or so. If you want to go na on it I can yank the 96es off my 350. They are 9.5:1 or so on a 455 although small valved. Those 4xes are presumably the big chambered heads. Any more it is likely prudent to use Edelbrock heads and aftermarket con rods.
Really? Seems crazy the more plentiful Pontiac engines would be so much more than a Buick. Bought my Buick 455 for $350.
 

Mr_Roboto

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Factory Pontiac arma-cast rods are toothpicks, even a plain old set of Eagle Ibeams double bottom end strength. Pontiac cast cranks are beasts regardless of the bad rap. Add some main studs and head studs, give the heads a deck and make sure intake side is cut appropriate amount also. Pontiacs make ludicrous low end torque with good air flow. Even a good bowl blend, port match and decent sized valve (issue with 350s small bore long stroke substituting 400 block gains many benefits) and proper cam and not getting greedy with duration and lobe center.
Pontiacs were NEVER designed for high RPM till Super Duty design hit. Like a Caddy engine its big, low end torque maker that will accelerate very fast if you play the parts right.
Pontiac rods will fail before cast pistons will!
IF you can locate a set of old #2095 326 heads you can get 10.5+ compression, still flow good and handle mid size valves.
Also dont worry about older Pontiac heads, after having had Pontiacs and building many sets I have yet to see unleaded hurt ANY seat. Just install good bronze guide liners and stainless valves.
Oh and most Pontiac blocks will spit down lifter valley sfter you start eclipsing 600hp!
Even a set of 5140 Tomahawk rods at $300ish are leagues ahead of the Armasteel rods, and way lighter. As in 200 grams a rod ish. In terms of cranks don't ever really recall them having a bad rap, most say 6-700+ on Armasteel for those.That said boost is easier on the rods than revs are, the reason being forces applied to the rods are to the square of the RPM. E.G. double the RPM quadruple the forces. That said, this will be done on what amounts to a $100 "rebuilt" long block, so I don't know if there will be too many tears if it spews. I should probably just say fuck it and run the Felpros on it now.

Pontiacs make great low end torque, but I would not go as far as saying good air flow. Ported up well they beat a set of stock L31s by a bit, stock they are worse than the stock heads on my 305. They are designed for velocity and not top end. All to feed 400+ CID in most cases. Touching a 350 in any way except to rip it out is oddball. They were definitely engineered for torque and low lift flow with 30 degree seats etc.

I have a set of 67 326 (140) heads, valve reliefs are an issue though. Not sure how confident I"d be in fly cutting my slugs for them. CR will be at 10.5:1ish as well which is too far for iron on pump unless you're doing some interesting things. The stainless valves kind of touch on another sore spot with Pontiacs which is the 2 piece valves.

Really? Seems crazy the more plentiful Pontiac engines would be so much more than a Buick. Bought my Buick 455 for $350.
Dude, you get me a decent Pontiac 455 for $350 I'll toss in 100 as a finders fee. It seems like a lot more pray to the Pontiac gods and the 455s are a lot harder to come by. I wouldn't be surprised if armasteel rods grenaded a lot more too.
 

Mr_Roboto

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Found out good and bad news today. Good news is after popping the head off it looks as if I scored a set of real 350 sized gaskets. The wtf is the head bolt shanks are fucking coated in rtv. What the actual fuck.
 

PJx5x

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Sce, Clark, or flatout for copper gaskets (that's my order of favorite too)

Cometic for MLS
 

MonzaRacer

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Unless you have some of real early 350 Poncho pistong they should be of a slight dish anyway. Also you can have a slight dish machined into Pontiac pistons as the machined chambers are very noncondusive to spark know as there are no hot spots like on rough cast heads. I would have figured any cam under .550 lift(most Pontiac heads top out unported in the .520-.530 range) and don't get greedy with duration. As in N/A use 260-280 duration 110 or 112 centerline and in .500-.525 lift range. Also testing with 1.65 rockers gives better idea on valve clearances. And composite gaskets with closed chamber and negative ie down in the hole should put it around 9.8ish if it's higher order up some .060 deadsoft copper gaskets, spray with copper coat and torque with head studs. Pontiacs don't deck walk like other engines.
 

Mr_Roboto

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Unless you have some of real early 350 Poncho pistong they should be of a slight dish anyway. Also you can have a slight dish machined into Pontiac pistons as the machined chambers are very noncondusive to spark know as there are no hot spots like on rough cast heads.

I would have figured any cam under .550 lift(most Pontiac heads top out unported in the .520-.530 range) and don't get greedy with duration. As in N/A use 260-280 duration 110 or 112 centerline and in .500-.525 lift range. Also testing with 1.65 rockers gives better idea on valve clearances.

And composite gaskets with closed chamber and negative ie down in the hole should put it around 9.8ish if it's higher order up some .060 deadsoft copper gaskets, spray with copper coat and torque with head studs. Pontiacs don't deck walk like other engines.
They're FTs. Virtually every Poncho ever made was FT. There's no "we'll adjust the compression with dishes" like a Chevy mill. The closed chamber heads will hit with the valve near instantly coming off the seat, so they would need quite a bit of clearance work. If I had some sacrificial slugs I'd be more willing to test it.

I'm actually really inclined to run the 43s be They also certainly paid money for a valve job to be done on these heads, at least the intakes are freshly cut with the bowls opened up. Perfect for me to get the carbides and sanding drums out and work over some. cause they have screw in rocker studs and see what they do. Compression would be in a territory between jack and shit though.

Cam wise, I have a 214/224 110LSA in the old engine, not sure what's in the "new" one. I'll see if I can get the ID marks off of it, but I may just swap mine in if it's not trashed with the old engine. I think it's plausible it's over cammed for the compression, but the old one ran okay N/A and knocked down a best of 17MPG highway on the qjet with 3.23s and no OD.

I popped the 43s off the "rebuilt" engine today, broke them down and looked at the porting work on the one head. The intakes are done conservatively, the exhaust appears opened a bit much but I'll live with that I think. I need to finish up the porting work, the heads have a fresh valve job too so that's nice. I need to get an engine stand, put the engine I got on it and check it out. I suspect that I'll find more RTV debauchery done by the bubba that built it.
 

MonzaRacer

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Actually I have owned and built many Pontiacs, even have set of used 40 over pistons still out on porch, have two sets of cast 77-78 400 pistons that DO have dish factory from GM. When emissions came in 8.5 was still bit high and dush dripped them to 7.8-1. and if you look at 60s up to 70/71 they came flat top 2 or 4 eyebrow. Just sold bunch of parts to buddy. Closed and open heads, different sets of new ,used, ? Pistons. We just picked up dished set 2 eyebrow pistons, cc'd the deck and one lc and on hc head. With stock composite gasket they came out 7.86-1 average or 9.8?-1. So he is looking to mod a set of flat tops with similar dish. I'll ask which part/casting number they are. GM did lot of odd stuff to keep storehouse parts workable through 70's and keep EPA happy. Do know buddy took 78 400 low compression, bolted to Muncie 4 SPD and oddball 2.41 gears in Pontiac (Nova) body and was pushing crap gas and such and had it tuned to 21mpg on highway. Sucked in town and cruising town would make his clutch stinks(he did have bigger GMC /Pontiac truck flywheel/12in clutch so it lasted longer) eventually in 80s he switched to different trans and 3.08 and look and behold it only lost like 1/2 mile to gallon but was much easier to drive. Now it has Keisler R&P 700 . Think get finally put FiTech 4bbl on it as his qjet intake warped.
 

Mr_Roboto

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My bad. Learn something new every day. I have 3.23 gears in the Lemans, so I'm doing a bit (not much) better. Those smog gears are bad.

In terms of the trans setup, what would you look for to get one of the bellhousing/clutch setups? Is the M15 (Saginaw) trans worth running, or is it the T5 of 3 speeds? Just weighing my options, I'm wondering if the T400 I have in the garage would be a smarter choice.
 

MonzaRacer

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Ok saggy-dog trans are weak kittens if you beat them. And shifters suck. Look around for Lakewood blow proof, standard flywheel and as for clutch, call centerforce for recommendations. But one of the dual friction units might just be the ticket. 3.23 gears are great if you build for lower end torque.
T5 never had enough torque rating.
Now if you have a th400 your on the way. Either get a manual and tackle giving it a rebuild. I rebuilt my th375( think th400 with th350 tail shaft size) I was given a Caddy 500/th400 by my old boss. I found it had bigger clutch packs(6/6/4 vs 5/5/3). So I got a Transtar rebuild kit (raybestos blue plate clutches/koleen treated steels,Kevlar band, up graded sprag. Also installed B&M transpack, set it up with highest step if valve body mods but instead of using a modulator valve block off plug I added back in an adjustable modulator valve. I then teamed it with TCI Saturday Nite Special converter. I put it behind a 402bbc built for torque w/3.55 gears. On street tires open headers and Southside Machine traction bars, both my buddies swear it pulled front wheels in my 70 Monte Carlo.
Attention to small details CAN result in impressive results. Horse power comes from an equation, torque IS the power to MOVE your car. Keep tires wide and under 27.5 tall and dual in suspension and it will haul ass.
With good internals a Pontiac on moderate boost like under 10psi (like 5-7) would probably push limits of stick driveshafts and street tires(ie cheater slicks may be required). Swap meets are great place to scrounge parts after you have plans set up.
 

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