[ap72]

It all depends in what you're looking for. For a mild street engine using a lot of factory parts 1hp/ci is a good rule... If you want 389hp then that will work, if you're looking for 450hp then more cubes will make a much easier job of it.

 

[ap72]

Torque gets the car moving off the line and that is what Pontiacs make.

They don't make torque or power any differently than any other engine, you can slap whatever brand sticker you want on the valve cover- its really meaningless.

If you want a good relatively low cost pontiac (or any other engine) here is a good basic recipe-


Stock rebuilt short block, may need to get it bored and new pistons (cast or hypereutic are probably fine), keep the crank and if you plan on going over 5500rpm or so get aftermarket rods. Pontiac oiling isn't the best, there are a lot of fixes, but the easiest is to just have the machine shop enlarge all the oil galleys and install a ported HV oil pump. If you do that be sure to also smooth all the oil drain back channels. Oil flow is NEVER a bad thing- it can and does cost a little power but it greatly increases longevity.

The next part is the heads, of course some are better than others but you're often stuck with what you have, especially with a relatively rare engine like a Pontaic. The good news is that for a modest 1hp/ci goal almost any of the heads will work- but you need to have a valve job done and I would get them ported too. You may need new valves and guide liners so expect that. You'll then want a good dual plane intake, the typical Performer RPM will work fine if you want to keep a carb, there's also good efi intakes if you want to go that route. Get a good street carb, for street only use a carb in the 600-700 range will be fine, for some track time go with one in the 700-800 range. I like the design of the new Street Demon 625, though I have not used one in the past, Edelbrock carbs are probably the easiest to use. Getting a set of headers will help a LOT but it may be a hard fit. There's a lot of power there though so try to find some that will fit if you can. For a cam, it depends on your final engine and driveline specs but for a mild street engine with 9.5:1 compression 220 degrees @.050" on the intake is about the max you want to go- going with a simple "RV cam" will make a very mild daily driver that will be down on power a little but they work just fine for cruising type cars. 1.65 roller rockers would be a nice addition too, but see what your budget allows.

For 389hp (or thereabouts) you don't need to get crazy on parts, depending on your final selection and tuning following the recommendations I gave you will get you close, perhaps over. Its very easy to spend 2 or 3 times as much and make more power but I don't know how far down that road you want to go.

 

[ap72]

I was typing when AP72 posted. A couple things he says need addressing.

Due to the length of the intake track, the shape of the port (a true "venturi") and the "long" connecting rod, the Pontiac makes more torque at a lower RPM than most American V8s. What makes the Pontiac "different" than the Olds and Buick (the only ones that make that level of torque) is the ability of the Pontiac to accept modifications. Not unlike a Chevy, when you add perfornace parts to the Pontiac, it responds well. Think of it sorta like a small block on steriods. But rest assured, ALL engines are different when it comes to the approach to making power. This concept "one is the same as another" is what got Pontiacs the negative reputation in the '60s, when small block guys left in droves as GTO stomped everything on the street. They would try to make power at a high rev and ignore the torque. This led to the feelings that Pontiacs don't "run" and blow up. And it's true. If you approach it like a small block, this IS what happens. Approach it from the correct angle, and you get the engine that powered GTO. And never forget, GTO didn't get a reputation for LOSING... No other muscle car has a mystique around it like GTO. In '64, add slicks and run 12s all day... Smokey said regarding the Pontiac, "Don't rev it up, GEAR it up..." Today, we do both...

The Pontiac oiling system is excellent, just misunderstood. The only change we make is to restrict the oil (at the lifter bore) when using a solid lifter. Like the Chevys, this prevents "filling" the valve covers and starving the mains. The 60 lb. oil pump is the true "high volume" pump, regardless of what is said in various catelogs. The 80 lb. pump is the "high pressure" version. I PROMISE you, Melling knows more about oil pumps than Summit.

Demon carbs should be avoided. The company no longer exists. It was never anything more than a genuine immitation Holley anyway. Rochester Q-Jet is among the better carbs for the Pontiac (single 4-bbl), and of course, 2GCs on the TriPower. Once the "need" for more than 800 CFM arrises, we use AED Holleys.

Don't mean to step on everything he said, but he's propegating erroneous mythology. Having built literally hundreds of Pontiacs AND Chevys (including record holders and track champs), I am in a good position to know of which I speak.

PAX

Jim

****************

The brand on the valve cover is irrelavent and pontiacs runners are NOT "true venturis" You can build either a chey 383, a Chrysler 383, or a pontiac 389 and if you do everything right end up with almost the same exact power. As for torque- well torque is a made up meaningless number, what matters is the average power but to the ground, regardless if your engine is buzzing at 5,000 rpm or 10,000 rpm.

Restricting the oiling is one method of oil control, supplying more is the other, enlarged galleys and a HV pump will take care of supplying more- regardless of what pressure you chose (60lbs should be adequate). fixing the oil drain back and emptying the valve covers is an entirely separate issue and should be addressed as such, there are many way to increase the drain back.

As for Demon, the company certianly is still around, you can contact them here: Demon Fuel Systems - Sales & Product Support Contact



40 years ago when not much was widely known about engine design your recommendations would have been spot on, but in the past 40 years a lot was learned and improvements have been made.