[Stan65]

So what I want to do is a basic rebuild. Want it to appear and sound original. So 4X-H1’s, intake, carb, distributor, and exhaust manifolds will remain. Want to go roller cam for dependability. So what’s everyone’s thoughts on what to replace, reuse, and upgrade.

I know the answers will be all over the place. I searched for a couple days and most rebuilds have upgrades that take away from the original appearance and sound.

Here’s my new to me Brewster D-port auto.

Thanks in advance,
Stan

[steve25]

The first to do is to get the heads check out for cracks, or even the start of a cracking issue since the 4 series heads where prone to that.

Your motor originally was fitted with the 067 cam if I am not mistaken, and if so then that small of a cam might mean getting a custom hydro roller ground up.if you want to as you say,stay real close to stock.

[mgarblik]

I will jump right in the deep end. You stated stock rebuild, stock look, sound and I assume performance. I see no need to replace anything with non-stock type parts to get the results you listed. This includes the switch to a roller cam. Why spend over $1000.00 extra to gain nothing? If your really worried about the camshaft wear, have your new flat tappet cam nitrided. You can re-use your stock connecting rods with new rod bolts. You can install stock replacement cast pistons in the size required. The single key to success is finding and using a really good machine shop that will actually do everything properly the way it should be done. That's the bottom line. When these engines were built the first time at PMD, they didn't use any expensive exotic parts. But everything was clean, properly machined and verified for a correct assembly. Heads already have hard seats. Probably need a set of guide liners and a quality valve job. Deck squared-up, line honed, nice torque plate hone and your done. Should make 240-250 HP and be stone reliable with about a 5000 RPM red line. So that's the basic stock rebuild. Probably about $1200.00 worth of parts. By the time this thread is over, I bet some will suggest $6000-7000 in parts to make about the same power. Hope you get some good ideas.

[Stan65]

Agree on the magnaflux. The block and heads are at the machine shop now. I don’t need to stay with the OEM cam specs, or compression for that matter. Just needs to appear and sound stock. I want a clean burning idle. I have hopped up cars already. I want to “restore” one for a change.

Thanks.

[Stan65]

NoBuddy,

308 auto with stock stall as original. As far as the EGR valley pan. I have seen 1 guy beat the crap out of the bottom (I would section and weld myself) and another modified the intake on bottom and plugged ports to be able to use the aftermarket valley pan.

Skip Fix,

Yes Algon large port. Have everything to go mechanical. Planning on EFI sometime when I get a chance. Lol.

[Stan65]

Mgarblik,

I will never build another engine with a flat tappet cam. My cars sit for long periods of time and the dry restart gets them most times. I have tried several things in the past to make them live. Comp zink additives, redline oils, even went as far as pulling inner springs and pre lubing. Just not worth it to me.

$1000 for a roller setup is already in the budget. Not trying for a budget build.

I’m looking into the Howard’s LS lifters and the ford spider/dog bones. link bar lifters won’t fit under the EGR style valley pan.

The comments I am expecting are exactly what you are expecting. New rods don’t cost much more than magging, straightening, new rod bolts, and resizing the original rods.

I am all for a little more compression and a little more cam. Just want a smooth idle and gobs of torque.


Thanks again. Keep the replies coming.

[Jay S]

There isn’t an aftermarket valley tray for those deep EGR setups that I can think of. There are options for 75 and later, those clear on some aftermarket trays.

Too clear the stock tray for link bars they hit on the edged right where the splash tray is spot welded to the top outside of the tray. Which isn’t easy to modify, and if you goof at all you’ll be looking for another one, and they are not easy to find any more.

On the 74 EGR we did, the exhaust cross was blocked off, then we removed the EGR well under the manifold. You can use what ever cover you want then. I don’t remember what I did on the intake port side to EGR, I think I weld them shut. Been to long. Lost a lot of weight though, that sucker was heavy!

The best option might be to remove the bottom splash tray, weld on a little splash guard underneath the PVC. (Butler has something like that on some of their trays). Then use sealer on the tray instead of a gasket. Without the bottom splash tray on the tray it is to flimsy to hold down a stock style valley tray gasket. But something like The Right Stuff Permatex gasket maker will work fine by itself, and probably leak less than the factory gaskets did, and it still would look completely stock.

[Formulas]

Those particular heads are about 115cc right?

I would be hard pressed to reuse them when 94 cc and 101 cc heads are abundant and wouldnt bust the appearance except for codes

your heads would need a heavy mill just to make half way decent compression

doesnt Butler offer baby rollers for near stock valve events?

[hurryinhoosier62]

You’d be better off with 6X-4 heads. To echo Mike, finding a COMPETENT machine shop is the crux of a successful build; if they start telling you to “trust them” run like hell! I have seen too many guys on here start the “It’s just a street engine” mantra when we engine machinists attempt to give them advice.Unless you have thousands of dollars to waste keep it simple. I haven’t seen a set of the Chinese forged rods that didn’t need a bit of “touch up” work on the small end or the big end. You can’t go wrong with Molnar connecting rods. Haven’t used a set, but all of my machinist buddies swear by them. Find a GOOD crank grinder who understands what being “on stroke” and “on spec” means. As far as roller cams, realize that cam billets are still in short supply. Don’t let anyone try to talk you out of using the OE iron intake; they are a good street intake manifold. Wash everything thoroughly, assemble carefully and grin every time you open the throttle!

[mgarblik]

Once you have had a bad experience with wiping out a flat tappet cam, I can understand the worry. Make sure your roller lifters of choice are up to quality standards as well. I have had plenty of roller lifter failures as well, but not many in the low spring rate, street stuff. Connecting rods, certainly there are much better choices than stock PMD, but they will need to be checked carefully and possibly touched up some. There are certainly many iron heads to bump up the compression some. A camshaft with modest lift in the .450 range and wide lobe separation range, 113-115 will get you the sound and smooth idle/big low end torque you desire. Good luck with the build. Of course all of the changes I just mentioned in this post move away from the "stock rebuild" you listed in post #1. I have also now at least tripled the cost of your rebuild from my first post and maybe gained you 25-30 HP. In the end, we all know the formula: How much power do you want to make? How much $$$$ do you have?. It is all fun though.

[PAUL K]

Originally Posted by mgarblik

Once you have had a bad experience with wiping out a flat tappet cam, I can understand the worry. Make sure your roller lifters of choice are up to quality standards as well. I have had plenty of roller lifter failures as well, but not many in the low spring rate, street stuff. Connecting rods, certainly there are much better choices than stock PMD, but they will need to be checked carefully and possibly touched up some. There are certainly many iron heads to bump up the compression some. A camshaft with modest lift in the .450 range and wide lobe separation range, 113-115 will get you the sound and smooth idle/big low end torque you desire. Good luck with the build. Of course all of the changes I just mentioned in this post move away from the "stock rebuild" you listed in post #1. I have also now at least tripled the cost of your rebuild from my first post and maybe gained you 25-30 HP. In the end, we all know the formula: How much power do you want to make? How much $$$$ do you have?. It is all fun though.

In addition a roller lifter failure can destroy the block and do considerable damage. A flat tappet failure may cause a teardown and inspection but I've never seen catastrophic damage from a failure.

[PAUL K]

Looks like a great project. Wanting my 73 Trans Am to sound stock, look original, retain most of the original parts and perform better than a Super Duty this is how I built mine.

The block was the hot tanked, checked, bored .030 and torque plate honed. I used a set of old TRW domed pistons that put the compression ratio close to 10:1. Original rods were rebuilt using ARP bolts and the original crank was used. The rotating assembly was balanced. Cam was a HFT 231 @ .050 duration .540 lift. The original heads were converted for screw in studs, ported to flow 240/180 and the exhaust crossovers filled. The original intake manifold was ported and the EGR bump under the secondary barrel was removed. The original carb was restored and the recalibrated. The original distributor was modified for quicker advance, the vacuum canister travel limited and a Crane electronic conversion kit was installed. I was lucky enough to find a set of H-O racing specialties tri-y headers. I used those with a mandrel bent 2.5 inch exhaust system using two walker bullet mufflers located where the resonators were on a 73 SD car and a high flow crossflow muffler with OEM tips.

Things I might've done differently..... Find a pair of 4X heads from a 400 with a similar date code that already have screw in studs. This would save the expense of converting the heads to screw in studs and allow a decent compression ratio with flat top piston and 87 octane fuel could be used. Reprofiled the cam to work with less compression and give the car a true "stock" idle sound....now it has a little bit of a rumble.

[Jay S]

Lee will set you up good on the cam.

You should consider working with Paul K on your pistons. Autotec. You can adjust the compression height to zero or negative deck without any special machining. Paul also is about the only one I have seen that deleted the valve reliefs on a low compression 455 to maximize the compression for the combination. I don’t recall which engine it was that he did that on. I think it was a 455SD. Taking 5 or 7 cc off the compression volume can make a pretty big difference in making the compression more what it needs to be and not milling and decking. The small cam that is going to be in this, with those 4X heads that deep chambers have more valve to piston clearance, you really don’t need valve reliefs. Jmho

[Lee]

I have a '73 T/A clone. 455, with similar spec "66" heads. I used the KB347 pistons, which have just enough "dome" (a slightly raised pad, more accurately) to zero out the valve relief, which give me a final CR of 8.3:1. Scat rods connect them to the stock crank. I designed a low lift cam (see signature) to be able to retain the stock non-adjustable valve train. I'm using a P4B intake with FAST EFI/ignition, but results would be similar with a well built Qjet & HEI. I do have headers (tri-Y) and a low restriction exhaust.

Anyway, it has made ~ 315hp/385tq at the wheels, and ran 13.1 with 3.08 gears & a stock stall, all on 87 octane.

[Stan65]

Thanks for all the info so far everyone!

Finished cleaning and magnafluxing the heads and block. All checked good.

Heads are In amazing condition. Guides are still in tolerance. Seats look good also. Will just have to setup and just touch them. I ordered Ferrea valves, F5079-8 and F5143-8. Will cut the exhaust for positive seals, set springs up, slight pass on the decks, and the heads will be good. At this point not cutting extra for compression.

On the block, did a rough bore on the “worst” cylinder due to rust pits. Cut it to 4.176. Can just make out the pits. Looks like 4.181 is a go. Now time to start piston shopping. Once I mock it all up, we will deal with the deck height to set quench.

Working with Lee on a cam, blanks seem to be non existent right now.

Once I get the block home, I’ll start working out the cam/lifter setup. I will have to determine what will work best, dog bones or link bars / valley pan modifications.

Just wanted to give an update.

[PAUL K]

Your in good hands with Lee. He has a lot of first hand knowledge in what actually works and doesn't.

Cores are hard to come by but they are out there.... There are several small grinders that you might want to check with. We got our last few from a company called Custom Cams. There is also another that bought all of John Reed's old equipment and masters. I can't recall their name but if you start calling around you'll find them.

[steve25]

The details I have found for the OPs motor are 112.3 for the chamber volume which makes for a 8.2 to 1 compression.

The cam indeed was the 067 grind, rated Hp was 250.

[Stan65]

Thanks everone thats responded so far!

My 4X heads do have factory screw in studs.

I suppose I should have been more specific in my first post. I am keeping all the original exterior parts as it will be a correct restoration (if they pass the magnaflux inspection). I would like bullet proof reliability by upgrading the "failure points". Examples I am aware of the flat tappet cam / lifter failures and I hope the lower lift and duration along with a non link bar lifter being lighter combined with a low rpm ceiling will make a roller last like an OEM roller engine. I am also fully aware of the factory rod bolts that are 50 years old so at a minimum I would replace them with ARP (which of course requires rebuilding the rods). While doing so if I can gain more performance that would be nice also. I also completely understand the intricacies of machining. I haven’t built a Pontiac for about 25 years, but its not my first. When I was building them the aftermarkets parts were super expensive or nonexistent. The best I could hope for was a set of SD rods and a N crank.
What I hope to get out of this is: “These” pistons with a 0-.010 deck and this head gasket thickness will get you the desired quench distance (.040"-.060". They will also increase the compression to roughly “x” if the heads cc to the original 115cc. (I understand changing to 6x-8’s is a huge improvement, but I really want to stay original).
I’ve also read up lately about that Pontiacs want for lobe separation with the low rpm torque-based design, and see that 112-116 degrees where 114 is probably a sweet spot.

Also included a couple pics of a 409 I’m building so everyone gets an idea of my capabilities.

Once again thanks all who have participated.
Stan

[johnta1]

Stuart, with the bigger cubes of the 455, your cam selection can be more than what a 400 would take. It would not sound as radical as in a 400.
I ran a pretty large roller in my SD engine and it wasn't much different sounding than the stock cam. With the higher CR later on, it was really nice.

I'd also talk to Lee, he probably can get a decent cam for you?

Hopefully I will be able to see it next year when I get up there again.

[Douglas Willinger]

GM, how about newly cast SD 455 heads!

Make some extra funds from what your corporation has already done the research and development.

Better yet, make them with 96 cc or 87 cc chambers.