Anyone ever really mess with one of these? Seems to be most people want to swap in a 400-455 instead. What are the effectiveness of mods on these such as head porting, cam, intake mods and headers/exhaust? I have a 71 with a 2bbl and a single exhaust right now. Everyone is concerned about tossing the rods out the side of the block with one of these, since it's a 350 and has less recriprocating mass what am I good to? It's going to be a driver rather than a racer so I really am looking for a bit of power to make it more fun.

 

You need to check out Butler, performance years.com and other sites. Prolly not many people know much about them on here.

 

They are just like a 305 to a 350, except worse.

If you can have a given chunk of cast iron and get 455 CID out of it, why would you want to take the same chunk and get only 350? Fails the simplest possible smell test, and goes downhill from there.

A 350 2-bbl is the worst case; low compression, poor flowing heads, etc. Best mod for that is to throw it in the trash and get something better to spend your money on.

After all, CID acts like an amplifier to Money. Remember the Basic Hot-rodding Equation:

Fun = Money x CID

Don't outsmart yourself with a bunch of "I've already got it it's free". The Equation is ALWAYS true.

 

Like sofa says, thats why you don't see many pontiac 350 builds. But there are people that don't go the cubic inches route. It took me a minute to find but High Performance Pontiac did a build awhile back. http://www.highperformancepontiac.co..._engine_build/
Note that it's a nice build but a typical SBC 350 would put down as good or better numbers for less money. But what people do with their cars is up to them.

 

For a nice fun street car thats not a bad motor. ESP since its a "stock" rebuild or "freshen up".
Good heads an roller cam would wake that motor up big time.

In highschool, my stock pos 73 formula 350, 2bbl, auto out ran a modded (intake, cam, headers, gears, carb and exhaust) 79-81 Z28. He was mad at me..

 

It would have been nice if they had used a cam that was a little less outdated as a 068 but get why they used it. Personally I never run a flat tappet in a new build anymore. What gears are/were in your formula? I'm gonna guess 2.73 or worse.

 

The whole "build" is really just a simple freshen up and the cam, well your 100% correct. I'm not sure what kinda power they expected with barely and bigger cam and midlength cast manifolds.. surprised it made that 4 power..

Yup, 2.73s, he had 4.11s fat tires and didnt spin!. He jumped me outa the hole and I pulled around him slowly.. He was cussn, and swearing to his guys that I was sprayn my car I could barely afford the gas, beer and condoms to operate that car back then...

 

About the worst thing you can do to a Pontiac 350, is put a cam in it.

If you do, I'd suggest looking at the wimpiest, lamest, weeniest thing you can find; maybe something like a Comp "Dual Energy" 252. Maybe even the Summit 194/204 cheeeeepie.

I recall one of those that a friend brought me that he had bought for his mom, would have been in the late 80s / early 90s... about a 70 or 71 LeMans 350 2-bbl, dark metallic green w green vinyl top, with all manner of the old-age and neglect problems, but otherwise a sound car. He had me put a Comp 260HE in it while getting the heads worked, rebuilding the carb, total tune-up, timing set, water pump, etc. etc. In the end, it had less get-up-and-go than it did when it drove in. I thought the cam was probably why.

Just bolting a bunch of hot-rod parts onto something is no guarantee that it will get faster.

 

Ain't that the truth!

 

The summit 194/204 cam is actually smaller than the stocker, and the Comp your buddy used is smaller than the 350HO cam used in 68-69, and is only slightly larger than the 2bbl cam I/he already have/had. They're not like a Chevy where their "peanut cam" is 179/195@.050.

Thats the reason I'm asking about this, not 100% sure with these engines or even 50%. The advice of "get more CID" seems to be what everyone says, I'm not concerned about being able to pass anything but a gas pump, just wanting a "bit more" out of this engine. A car with a runnign 50hp engine still has more power than a car with no engine waiting for a 1000hp engine.

I'm honestly very curious to see if the carb/air intake system are going to be restrictions with the stock 2bbl. I'm planning on hooking the vacuum gauge up before I think about the Qjet honestly, rather than just assume it's the case. May be surprised at what I find. I've heard the smaller primaries on the Q-jet are good for about 1-2mpg on these though, so may end up doing it anyways. Who knows at this rate; about the only sure thing is I'm swapping to HEI from points. It's easy to do, I can fudge with the curve a bit while I'm doing it, and supposedly they're better all around.

Lastly, this isn't a SBC/BBC. Based on what I've been reading there's actually not a "ton" of variance between parts on Pontiacs. If I went as far to port/revalve my heads I could put them on a 455 later and likely not see much if any penalty for doing it. From what I've read keeping stock Pontiac 2 piece valves is probably a bad idea anyways. I could also buy an intake, some headers and so on and they'd work fine on the 400/455 down the road.

 

If you're not looking for power then I'd say find a random small block since there's a lot entailed when fitting a pontiac in our cars but...since you seem to like this engine then I'll dig deeper. A qjet will have a better throttle response than a dualjet due to the smaller primaries. Gas mileage is iffy since you know you're going to open the secondaries now and then. What kind of condition is this motor in? What year is this motor? The 350HO in the article has the best heads any P350 had and they are still tame compared to a good aftermarket head. The heads on yours are even more lame and count yourself lucky if you have 6X8 heads. 6X8's are/were popular for 455 guys cause they were cheap and could be made to flow OK. Now by today's standards all aftermarket heads blow away stockers cause price per CFM is better than a rebuild/ported factory. The problem with aftermarkets is they were made with 400CI as the smallest likely engine to be used on, so the 350 wont's move enough air to make the most of the ports. I think its a lot of effort to put forth for an OK engine that you've already thought about changing for more cubes. Pontiacs are lot heavier than SBCs so count that as well.

 

Never said third gen. There's a lot of smart folks here and it seems as if the info out there for Pontiacs on the net is very single sourced, so I'm trying to get some second opinions. Some of the info out there seems pretty mixed for the Pontiac stuff, I'm finding sources that say one thing and are either incorrect or contradictory.

Overall health seems good, she sat for a year and fired right over and idled smoothly. I've been doing some body work on the car so I haven't really driven around a ton.

Not looking to go that deep into this, heads are a big bank proposition when you start talking about KREs, Edelbrocks etc. I can build one hell of an engine for that kinda money be it Pontiac, Chevy or other. It's not an all out power build, just a "bit more" from a fairly stock engine. The low hanging fruit if you will. If it were, I'd be putting rods in this so I could spin enough RPM to use nice heads like that. Yeah the head flow looks abysmal but based on the rule of thumb you should be able to get ~2-2.2hp/CFM of head flow on a V8 which means I should be able to get up to 275-300hp flywheel without an absolute ton of trouble.

I have No 94s which are small valve heads, 96cc chamber and about 8.2:1 CR based on what I can find. My big concern is the valve train, it has 3/8 press in rocker studs, so obviously without yanking heads and getting em set up for screw ins I'm not going to be getting a giant cam or spinning this to the moon. I'd say I'm probably going to be limited to ~5500 RPM for red line. It's also the stock style guide plate heads. I was thinking about the Howards 213/223 cam for this, it has .450 lift and a 112 LSA which puts it fairly close to an 068 cam duration wise and lift wise it's a bit higher. Based on the #s I've seen for Pontiac heads (even small valve) that is a pretty good spot to be at lift wise. With a set of valve springs, some poly locks and maybe some adjustable push rods I think it'd be a decent match if I went and got some headers to go with the Qjet setup. I am also running a manual and based on what I can determine a 3.23 gear ratio, if that makes any difference.

 

Sorry, I always think people only work on thirdgens here, as if life doesn't throw other toys our way. I wish I had more info on the no. 94 heads to give you better advice but it looks like you have an ok grasp of what you want to do. I do know that most pontiac cams were larger duration but relatively low lift. Only HO motors like RAIV's had high lift, so .450 would probably be the MAX I'd want to run. What cam is in it now? That might be a great cam for it as it stands. Low compression is a killer to many aftermarket cams. Pontiac cam designers knew their engines very well back then. If you don't want to dig too far into the engine then just think about a good q jet, fresh springs and maybe headers or RAIII manifolds. Ram Air Restorations make an oversized set that are nice (I have a set) and they flow close to headers. Curve the HEI for best results and drive!

 

What curve are you using on your 400? I think it'd need tweaked a bit for the 350, but would be an awesome starting point. Based on what I've read I need to get a mech advance limiter, have it come in earlier and decrease the vacuum advance.

I emailed Howards and asked about the cam. It turns out that it's a stock base circle cam which I believe means it should work with my non-adjustable valvetrain all right. I'm thinking about going with 98432 Howards springs, they are 135# installed@1.75 and appear to be 285 at .5 lift. They also have another PN listed with a different OD and installed height. Any idea if I can use these springs? The specs on the others look pretty meh overall so I'd much rather use these.

 

The one thing you must remember with ANY Pontiac V8 is they are not mean to rev in stock form. They built gobs of torque as they were originally designed to move big heavy cars. The reason they get a bad rap for throwing rods out of the block is people who were used to taking SBCs to 6000+ RPM did the same to a Pontiac and it blew it up. They were designed to make all the power by 4500-5000 max. Keep it below 5000 RPM and it will live forever.

The Pontiac 350 is somewhat of the red headed stepchild with the only thing worse being the 326 or the very worst 301. But as you said anything that will bolt to a 350 will bolt to a 400 or 455.

I would try and find a set of 6X4 heads which have a slightly smaller chamber than the 6X8s. The 6X4s were actually meant for the 350. And is a popular mod for 400s and 455s to bump up compression. They will flow as good as your standard KRE or edelbrock head out of the box. The only downside is they are heavier than an aluminum head.

If you were to build another motor your best bet would be what I did. Get an early 400 block and stroke it to 461. With modern lightweight pistons and forged rods it will be good to 6500 RPM all day long. The 400 block is stronger with the smaller 3" mains and the smaller main is better for higher revs.

The final thing to remember is building any Pontiac V8 is expensive when compared to building a SBC. Price wise it is similar to building a BBC.

 

I don't remember what my 400 is set to...but thats kinda here nor there since my factory setting for initial is 20* withOUT the vacuum advance attached. The camshaft in a W72 is nontraditional compared to earlier cams so my timing seems wierd. Your 350 will like a curve based on its components, check with D.U.I distributors, they make a good HEI and know curves well. As far as springs I'm not well versed, I use whatever manufactures or machine shops tell me to.
And LilSki...just because I like to play devils advocate... SD455's, RA IV's, SD421's, etc all revved at least to 6K. But you are right the average run of the mill pontiacs only rev to 5K max.

*EDIT* its at 18* initial not 20*. Good thing the tab goes to 20.

 

Those heads appear to be 92cc which is slightly smaller than what I have now, however they also appear to be big valved. They would also have screw in rocker studs which means overall they would be a very nice upgrade if I can score a set for a decent price. Trying to avoid getting into that right now, only reason I'm going to do a cam is if this one is flat lobed.

Howards confirmed this is a stock base circle cam, which is awesome. I believe that means I can use my stock valve train with it. Springs I'm not too sure on, they list 2 different diameters and installed heights. As far as I can find out the early heads may have used a shorter, smaller diameter spring? Is there a way to find out without measuring? Looking at 98432 which is a dual spring w/damper and has 135@1.75 installed height and 300lb/in rate so I'd be looking at 270 lb with the valve open@.450 lift.

The other springs for the small pockets are 105@1.625 installed height and 263lb/in. That means at .45 they'd be 223 lb when open. Seems low to me.

Yeah the SD 455ss are their own beast; they didn't use Armasteel rods, which is one of the reasons why the rods are so rare today. Makes em a bit of a ringer IMO. I intend to be "done" at 5500 tops. That's all I have the nads to think about revving this to. Even the HO 350 had a factory red line of 5200 I believe.

The biggest criteria of this engine will be it runs, not that it makes end all be all HP LilSki. If I wanted that quite frankly I'd take it and turbo this engine. I have a "I modified the hell out of it now it doesn't run" project already, don't really want this to become another one.

 

I had a 350 in my 70 firebird, it was pretty torquey, I think the heads are the restriction, although the H/O 350's had upwards of 330 hp. Try http://www.classicalpontiac.com/ for tons of info on poncho motors.

 

Unless you know the guy on the factory line that assembeled the engine and know 100% that it's never ever been apart in 42 years, then you can never trust literature or hear say of what that engine has for springs. Or pistons, cam, heads or anything internal for that matter. The factory wasn't reliable for ALWAYS putting in the "correct" parts on a car. And 42 years is a long time to never have an engine apart. So my suggestion is to pull a valve cover and measure.

 

If there ever was going to be an unaltered engine this world ld be it tbh. The whole car is unmolested pretty much.

That being said I found out Pontiacs use 4 differing valve lengths. That means installed height is gonna be hairy without measurement.

 

Remember from the factory Pontiac valve trains are not adjustable. They have a bottle neck rocker stud where you torque them all to 20 ft/lbs and you are done. When changing cams it is usually a good idea to change to an adjustable "chevy" style valve train.

 

That depends on the year of the motor/heads, not all were bolt down. Kind of a trick question/ answer because its truley rare.

 

Well the vast majority anyway. Most likely his run of the mill 350 is that way.

 

I got a set of #140s off a 67 326 engine. I think they'll be ~72 CC (need to check) but that'll get compression of my 71 350 significantly closer to 9.5:1. First off, it seems as if Cometics are my options for HGs and that the Victors that are small bore are long gone. Any options I'm missing? Would really rather not spend $200+ to get some gaskets that are the right size and the Felpros that are out there look like a terrible alternative.

Besides this, what is the best way to go about porting these heads? Most people say to read Jim Hand's book on the topic, but it's markedly difficult to find these days and expensive when you do. Anyone got any real world suggestions? I know that the AIR injection potrusions are getting removed in the exhuast, I think I should raise the roof on these as much as plausible and am not quite sure where to go from there. The bowl/throat areas of these heads actually don't look terribly dimensioned overall, the pushrod pinch seems super tight though. As in I may need to epoxy in tubes for the pushrods tight. They are small valve heads which I believe were 45 degree seat angle, so does that mean I should get the valves back cut like people typically do with SBCs? What works for a valve job with these as well typically?

Also, they don't have the pads like my later 71 heads do for pushrod guide plates. Will I be cutting the stud bosses down, getting heli coils stuck in and rethreaded in order to actually run screw in studs/guide plates? Long term I'd like to have the ability to run higher lift cams and run this higher RPM if at all plausible. I know that I'm rod limited but you never know what the future will bring in terms of a short block.

 

Ah the pit falls of a small bore pontiac. To be honest with you I'd rather spend the $200 on gaskets just to know it's right.

Not to question your skills or abilities but do you really want to put that much effort into those heads? Might be better left alone.

 

I thought I had seen a page by page pdf of Jim Hands book. I couldn't find it but I did find someone doing a step by step using Hand's book. He uses 6x heads so its a touch different than the 140's. Hope it helps.http://www3.telus.net/68bird/engine_heads.htm

 

"Fulper has assembled an awesome package that makes nearly 540 hp on the dyno and runs high 11s in the quarter--without nitrous. Adding just a small amount of squeeze boosted the output to 670 hp and mid-10s. Here's what goes into making a brave little Indian (or is that a little Indian brave?)."

Read more: http://www.carcraft.com/techarticles...#ixzz2tbJCnGPZ


I have a '72 Olds with the 350 waiting at home for some TLC but the Olds is a bit different.. it has a 4.00 bore like the SBC.

However for a max effort race car the other GM V-8s are poor choices simply because the SBC & BBC have way more aftermarket support (better/stronger parts than OEM)

But for an original restoration to a classic car, or just a nice street cruiser there is no problem with "the other V-8s" IMHO. I would not race with one simply because it will cost more to build it and when you break it, it will cost cost more for the redo.

 

Yeah, BOP V8s are their own animals compared to each other or Chevies. Olds motors are cool, my buddy has probably 3 350 blocks. I'd love to talk about getting one or two off him especially if he has a large lifter block. (Basically the ultimate in Olds blocks short of some of the stuff they produced for racing.) Jam a 425 crank in it, punch the snot out of it and throw as much forced induction as you can muster on to it. Big cubes and a small (ish) durable package.

With this engine being ~355 CID stock I am under flowed at 190 CFM for turning even moderate RPM (don't forget a 455 HO (NOT an SD) had a redline of ~5500 on stock rods. Considering I have way less stroke and way less piston to add force to the rotating assembly I'm really inclined to think that's a fairly sane target for peak HP.

http://users.erols.com/srweiss/tablehdp.htm

According to this chart For every 10 CFM I gain in intake flow I'll probably gain about 230 RPM of capability, which means if I gain 20-30 CFM I've gained 5-700 RPM of useable RPM which is IMO a big deal. While I don't expect it to be dead nuts accurate based on a few other rough hewn math formulas I've tossed around I doubt it's a ton off. I also think that based on what I've seen there's a significant amount of low hanging fruit in these heads as with most older ones. The exhaust is horrendous and based on what I'm seeing of Jim Hand's stuff he is saying that you can cut the exhaust ports to be 1/8" taller and not even touch the floor. Considering you can look through the ports and not even see the exhaust valve stems I'm far far less than surprised there's big gains there.

The other thing is I'm running 1.92 valves for the intakes. I've heard these are 2 piece valves and susceptible to issues in heavier duty applications. What's the thought on digging up some 1.94s for an SBC with an over sized stem, getting the seats cut for em and throwing em in? If I get something with some performance characteristics it's possible I could get 10 CFM pretty easily in the low/mod lifts. They are a bit longer but if I shimmed the springs I'd think they would work fine. Also anyone run stock style SBC springs on one of these? Thinking of doing some beehives to try and cut some valvetrain weight down.

 

The problem is no matter how much porting work you do the Heads. the OEM design is "poor" compared to Chevy heads.

Compare exhaust port / spark plug locations for one.

From a service standpoint the BOPs heads are nice. You have great access to the spark plugs because they are above the exhaust ports and no clearance issues with exhaust manifolds/headers compared to SBC. The BBC is not as bad because of the larger bore spacing, head size, etc there is just more room for the plugs.

But from an airflow stand point this is a bad because the exhaust has to make a 90 degree turn. This reduces flow, it can be "smoothed out" but because of the design cannot be eliminated.

Remember the 2 keys to HP .. Camshaft & heads.. they need to be matched for the intended use..

Obviously a power adder helps overcome this shortcoming but a good cam and heads are still critical.

Pontiac motors also have a less than ideal rod / stroke ratio. (especially the 400+ motors) this is affects RPM potential more than anything else. Incredible low end torque but no high RPM power..

 

I would lay far more credence to the idea the heads are the fundamental flaw in making big power on these engines short of durability. If you want to think rod length theory longer rods supposedly provide detonation resistance as well as other benefits that can counter downsides. The article you posted is proof of that IMO, over 540hp from a 368 inch engine definitely proves that aftermarket heads are worth their weight in gold on these engines. Regrettably not in my budget though so makin use of what I've got.

That being said I'm not trying to feed big block cubes with heads that flow less than a set of Vortecs either, I'm trying to maximize my bang for the buck on a 350.

Besides, I'm not 100% on this right now anyways. I have a set of GN turbos out in the garage that may really be the best way to coax any sort of real power from this thing.

Figure I'd post this up since I found it interesting. These heads have emissions stuff in em in 67. From what I found out these are smog pump passages to help with more complete burn.

 

The "best bang for your buck" would be to not waste time / money /effort on porting OEM Pontiac 350 heads, but rather invest in a good set of aftermarket ones.

Just like Olds & Buick there is not a specific "small or big block"
so aftermarket heads for a big cube Pontiac will bolt on to the 350, just like the Olds motor.

All you have to do is get the heads milled so the CC is good for the smaller bore of the 350. A set of Edelbrock Pontiac heads would be far superior to the OEM. The only issue is you have to use the correct headers.

Just my honest opinion. save up for the good heads and you will have far better results.

 

for less than $1,200 assembled heads thru Summit.
http://www.summitracing.com/search/p...ontiac%20heads


Info from Edelbrock's site with flow data:

http://www.edelbrock.com/automotive_...erformer.shtml

or the D port heads... they flow about the same.. but there is a note that the
350 block may need notching for valve clearance

http://www.edelbrock.com/automotive_...former_d.shtml


I would say this is a bargain for a full set of heads on "street" car on a budget.

Considering I paid more just for my shaft mounted rockers on my Brodix 18 degree heads.

 

Some more info for your insight: A great article written by none other than
Steve "Magneto" Magnante

http://www.highperformancepontiac.co.../photo_08.html

FWIW the 3.875 bore is still BETTER than a 3.750 bore of the 305..

BUT a 4.00 bore or larger is still king.

 

Umm that's 1200 each. They're not SBC heads, for 1200 the set it'd be way more tempting and make a ton of sense. They are something like 215s though which means at that point you may as well build a 400+ and really use them. What I should probably do is see if anyone has a set they're ditching at a swap meet. The HO 350s had bore notching for big valves so that's not entirely anything new.

 

LOL!

I guess now you know why there are all these Pontiac 350s laying around

Cheaper to build a Chevy.

 

Yeah, no kidding. Then again I figure she'll probably take enough nitrous or boost to keep me happy for a while. Even an SBC is somewhat of a non builder these days unless you're real careful/have parts already compared to an LS engine. Aluminum heads, durable bottom end, light weight, roller valvetrain and even the small engines are just shy of 300hp. For the price you can't hardly beat that with a stick.

 

The LS is a great engine, but a bit over-rated IMHO.

it is still just a OHV, pushrod engine, but with a Ford firing order, swapped exhaust port locations on 2/4 & 3/5. To me from the outside it looks like a Small Block Ford.

The real key to the LS success are the OEM Cylinder heads which are far superior to the OEM SBC units.

My builder has done a few LSs already and in his words.. "It's just a glorified SBC with great factory heads".

 

I would actually call it a Glorified Windsor with great factory heads. Shoot Yates designed them from what I heard.

 

yes the Ford small block similarities are ironic..

What's old is new I guess at Chevy..

at least it is just a glorified Windsor and not a glorfied Cleveland LOL.

I grew up with one of those. My Dad used to have a '69 Mustang Convertible 351C & with the 4 speed.
To call that car "badass" is an understatement.

 

OK, going to throw this up and see what you think about where I'm going with it. Pardon the length in advance all.







First pics are of a rubbing a standard D port Pontiac. I've taken some measurements of the ports and used some circle templates to get a rough idea of the CSA of the port. I came up with a CSA of ~2.38 inches at the opening. It's somewhat hack but in the ball park.Basically I divided the top and bottom into half circles (which the port approximates) crunched the area and added the middle to the area of the circle. After calculating the ID of some 1.625 16 gauge header tubing, it comes out to 1.67 inches of area. Taking the assumption that the area I'd be working with is 1.25" wide, I have an area of ~.57 inches that the port is over sized. This leads into the next set of pics:







The socket extension is to make everything more visible, and to give a size reference. As you can see the port dips down into a huge hump which is likely a huge dead area. I am thinking about tossing a slug of metal in here, either a piece of steel that would get welded to the header flange or pouring aluminum in like people do with exhaust crossovers. I think the latter is probably a bad idea, but figured I'd see about some opinions on it. Jim Hand recommends raising the port roof ~1/8 inch so I would probably try to take that into account up to the point it hits the top of the "hump" in the port. How would something like that compare to the round port heads?



Pic of the bottom of the pushrod pinch hole. The top has an oblong shape cast into it, which defines the pushrod locating. The question becomes now can I keep that and still throw some tubes in the head so I can enlarge the runner inlet. Also, will it matter much. The CSA of these runners is actually very small compared to the valve size even at 1.92, so I don't know if it's a good idea or not to try and knock back the pushrod pinch a bunch. Quite frankly it may not mean much of squat, just because of other restriction in the port and the relevance of the lift.



Moving on to the exhaust on the chamber side, the port shape seems to favor the cylinder wall side pretty heavily. There's a huge bump (as seen here) in the port as well as the guide boss being significantly closer to the runner on that side. This is a middle port, if you notice there's actually a full out ridge here. I suspect smoothing this area down will see awesome bang for the buck considering that it is a sharp corner as cast. There is actually some potrusion of the port on the cylinder wall side, which is in line with what I've been reading from Vizard. Cleaning up the guide some, knocking back the AIR ports and smoothing that out a bit more shouldn't hurt. The transition into the bowl from the seat also looks a bit rough and I suspect smoothing it over wouldn't hurt a ton either. Just gotta try to keep from widening the throat a ton.



Just a bare shot of the intake port/chamber. You can't really see it in this pic but there's overhang from the top of the chamber with a sort of ( shape to it.





Vizard says that to fully deshroud a valve you should have .2D (or around .4" in my case" around the valve at .25 lift (or around .480 here.) The actual end of the socket extension is .375, so it's less than 1/16 off which gives a good idea of what we're working with.



The silver disk is ~2.3" diameter. To be in line with the .2D I'd need something about 2.7" diameter, or another .2" or so radius. Overall this head actually looks fairly close to having very little chamber shrouding although it's closed chamber with the small valves. My game plan is to find something closer to that diameter and see how it looks. The pen actually worked out really well, it fits the hole for the valve stem perfectly. How odd. I really am thinking about modifying a compass of some kind in order to draw a radius and try to figure out where I want to cut. I wish I had a cutaway view of a closed chamber head so I knew what my risk of hitting water is.

The last thing I need to figure out is if the bore is centered to the head bolt locations. I don't think I'm going to get a HG that's 100% true to the bores of the engine without going full custom. I found out that 301 gaskets are still out there and have a smaller 4.1" bore gasket compared to the "universal" stuff for a 455 down. It would be nice to be able to mark the bore location and determine if grinding is gonna intrude past it.

 

I think I have a Weiand four barrel aluminum intake for the pontiac motors laying about, they run like 500 and some new, so far as I can tell, this one has never been on an engine, it's just been hanging out in my garage for the last decade or three..... Sell it for 200, if you want it.

 

Years ago... I would say 2001 or 2002 Hot Rod or Car Craft wrote a great article comparing V8 builds from GM, Ford, & Mopar. (big blocks, small blocks, and the BOP engines) including vital stats (bore, stroke, block weight, dyno #s, & cost to build) it was a great reference and I had this edition in my Library for years.

Suprisingly I remember the Buick 455 being the "sleeper" in the GM fleet, performing on par with the BBC. The Big Pontiac engines: LOTS OF TORQUE, more than any other GM motor but no HP up high, also one of the more expensive to build.

I think if I search my 831 posts.. I may have posted it back then... LOL can always try Hot Rod's or Car Craft's website

 

Cool

 

Dig the pontiac build, everyone has a sbc or ls. Nice to see something different

Build /cam it for torque youll be real happy.
Theres room for imprvement in those heads from the pics.

as said most blew them up cause they tried to wind them up.
Do the best you can with those heads, 4 bbl intake. Crower has some nice cams that work with those, ask for an old timer there.
They make good toruqe on the st. My old built 327 camaro could only go neck and neck with a well tuned 2 bbl 326....yep. Torquey sob.

 

that's because GM wouldn't allow DeLorean the money for forged components