I'd join the local pontiac club..
they'll know who's goodand local..
and whom to stear clear of..

 

Sam,

The 350 is okay. In a Firebird, it can be a good performer. However, if you're not going to keep the rest of the car "numbers", you will spend the same amount of money building the 350 as you would a 400, with about 25% less "return". 400P is arguably one of the best "muscle car" engines produced during the era.

Set compression to 8:1 for 87 octane. 9:1 for 93. This is done by controlling the size of the "dish" in the piston. Comp's XE256H is an excellent cam for the 350.

The March surpentine system if very good. It fits and works, though not cheap.

Your car will retain the most value if you rebuild it "stock" (not necessarily internals, but appearance and numbers).

The trans SHOULD be a TH350 (M-38). That would be a 3-speed auto. The pan is a nearly square unit with one corner "lopped off". If so, plenty adequate for a mild build. If a 2-speed, it would be Super Turbine 300 (NOT PowerGlide). That one would be better being replaced by a TH350 or TH400.

The TriPower (3 2bbls.) is better suited to larger displacement engines and would be "overkill" on a 350. The factory Q-Jet intake and the Q-Jet would be a better performer. The "log" exhaust manifolds aren't the hot lick for HP, but very reliable and quiet. If you want more power WITHOUT headers, the factory "HO" manifolds are very good. They're available from Ram Air Restorations in TX, or Ames Performance and Perfomance Years (best sources for Pontiac-specific parts). These are good companies, and won't sell you Camaro parts because "they fit". They will also give an honest review of the overall quality and suitability of what they sell, unlike most resto houses.

performanceyears.com

pontiacstreetperformance.com

pontiaczone.com

transamcountry.com

transamtown.com

These are but a few of the Pontiac-specific forums. Some are sales-driven. Most are not. Good information exchange is there. I like psp (the second in the list) the best, but there are others that prefer the 'big" one, Performance Years. More hard-core racers go to "the zone", less resto and street.

You will get good AND bad reviews regarding our shop (Central Virginia Machine Service). You make your own choices.

Jim

 

A word on the casting numbers. The heads should be '47' seen cast onto the top of the center two exhaust ports. Some of these heads had 30 degree intake seats and others had 45 degree seats. The "Left: A319 Right: B069" codes you found are actually date codes, indicating Jan. 31 and Feb. 6 of a year ending in "9", 1969 in this case, and that's a good indication they're original.

The block code for a 3-speed M-38 AT is XL or XB, the 2-speed M-31 block codes are YJ and YE according to Pontiac Musclecar Performance By Pete McCarthy and John Angeles. Another site lists XR,XS,YN,YU but doesn't differentiate between which AT these are for. More info on Pontiacs including codes and their location can be found HERE.

I wouldn't limit myself to the 350 Pontiac just because it was what came in it originally. Some of the most potent production Pontiac engines were made in 1969 and installed in the F-body. In fact w/o a build sheet, I'm not even sure if there a way to know what displacement V8 was used- but that need verification. So while a 400 is not original, it could be considered "correct". Semantics, I know- just saying.

In any event, you would be the only one who knew what it had originally and IMO as long as you didn't try to sell it as an original 400, RA III or IV it really shouldn't matter. And I have little doubt you'd enjoy a warmed over 400 more than a 350.

 

Jim (Mr. P-Body) is too modest as he http://www.centralvirginiamachine.com/ is one of the, IMHO, most trusted Pontiac builders in the eastern US. Others are http://www.jbp-pontiac.com/ Jim Butler and https://sites.google.com/site/ksmsinc/ Ken Keefer.

 

A word on the casting numbers. The heads should be '47' seen cast onto the top of the center two exhaust ports. Some of these heads had 30 degree intake seats and others had 45 degree seats. The "Left: A319 Right: B069" codes you found are actually date codes, indicating Jan. 31 and Feb. 6 of a year ending in "9", 1969 in this case, and that's a good indication they're original.

The block code for a 3-speed M-38 AT is XL or XB, the 2-speed M-31 block codes are YJ and YE according to Pontiac Musclecar Performance By Pete McCarthy and John Angeles. Another site lists XR,XS,YN,YU but doesn't differentiate between which AT these are for. More info on Pontiacs including codes and their location can be found HERE.

I wouldn't limit myself to the 350 Pontiac just because it was what came in it originally. Some of the most potent production Pontiac engines were made in 1969 and installed in the F-body. In fact w/o a build sheet, I'm not even sure if there a way to know what displacement V8 was used- but that need verification. So while a 400 is not original, it could be considered "correct". Semantics, I know- just saying.

In any event, you would be the only one who knew what it had originally and IMO as long as you didn't try to sell it as an original 400, RA III or IV it really shouldn't matter. And I have little doubt you'd enjoy a warmed over 400 more than a 350.

Update:

Heads: Left side had GM middle had 4 and 7 and then it had the A319

Block had the 051068 and below this was YE

Also on the front of the block the VIN number is stamped on it. So everyone does know if it is original.

SAM

 

Desires:

Want it to last, low maintenance, use regular gas, but have enough power to have a little fun with it when I want to or need to.
Will have PS and Air Conditioning (AC recommendations?)

I also know everyone has their own thoughts on this, so I would love to hear them and if you want to PM me that is great.

SAM

When I go to these builders websites it gets confusing for a newbie. How do you know what you need and what is nice to have and lastly what you don't need?

They always list options and upgrades and it is tough to navigate through the selections.

For example, I went to:

https://sites.google.com/site/ksmsinc/engines

And

http://www.jbp-pontiac.com/services.html

I think the top site is easier for the newbie.

Can some let me know which 400 or 455's I should consider and which options if any? Also, if it should be totally set up and tested or broke in.

Remember I will have AIR and PS.

Thanks for any help.

SAM