What cam and heads do you run with tri power
 

I would like to know what heads and cam you are running on 400 engines.

Thanks for your replys

The 068 is what I like along with heads that will give you around 9:1 compression. If this is a street car, don't fall for the big cam high compression deal. It will shake, stall, stink and suck gas.. Keep it stockish. I liked the Nunzi 2041 cam http://ronspontiacpage.com/reference-pages/nunzi.htm
Have the exhaust heat ports filled and keep the compression in the 9s.

I have a 1978 truck 454 in my 69 el Camino, th400, 2:87 its low compression but it goes and I never had more fun with a car.

There's a Pontiac web site that has all the head numbers and descriptions. I think it was called Wallace or Rons Pontiac page.. Pontiac made a lot of real cool heads for that motor so your in luck..

The Summit 2801 is also an excellent cam for a 9:1 compression 400..

I have sold/installed a bunch of the Wolverine 744 High Lift Camshafts that were ground by Camshaft machine Company for Wolverine. A bit more lift, a nice MILD "slightly rumpy"
idle and makes for a great street driver.

Tom V.

I see the Nunzi 2041 is pretty close to the Crower 60242 which I was going to recommend.

If you’re looking for a little more cam than the Crower 60240 that you’re currently running as you stated in another thread I think you might be disappointed with the Summit 2801 or the 068 cam, both of which have specs similar to your 60240.

Either the 2041 or 60242 would be a big enough change to feel a noticeable performance boost, but not so big that you’d need to start modifying the carbs other than perhaps a jetting or metering rod adjustment.

For myself I chose the milder 068 cam because it fit into my combo of a low-compression 421 (8.8:1) backed by a 13” Continental converter, a TH350 and 2.56 8.2” open rear (later will swap to 2.73 8.5” posi).

I did it the other way - I talked with Mike Wasson (quite well known on this site with PontiacTripower.com) and told him what I had for a 67 4 speed WS motor with worked 670 heads - he asked what cam I had and how the heads were done and he helped me set up the center carb to match- runs great- hugely helpful. He is the expert -
Thanks Mike.

OK what cam are you running? I have a couple head options just looking to see what people are using.

Thanks

Hard to go wrong with the 068 H.O. cam in a 400 w/Tripower.
Running this combo with #48 heads in my 66 GTO w/3.07:1 12-bolt posi and TH400.
With 3.90:1 or higher numerical the 744 Ram Air cam will do well.

My cam specs are advertised Intake Duration 284 / Exhaust 296
Duration at .050 - intake is 240 / exhaust is 246.
Valve lift is .507 Intake / .510 Exhaust.
Lobe separation is 110
I believe it is Comp Cam XE284H

I originally was not going to run a tripower but decided on the wow factor and put the original 67 numbers matching intake on the shelf.

Here is what I have and did:
I have a numbers matching 67 GTO WS 400 with the stock 670 heads worked by a local head and engine specialist to run stock compression on really good pump gas.

Based on the aggressive cam I was using I had to make some modifications to the original 66 tripower idle circuit and jetting.
Using the original engine block and heads was important to me as I wanted it to look stock when i opened the hood. However, I wanted a 425 hp engine to run on pump gas.
With the advice of the engine builder that did my head work, to achieve better performance, I was directed to a more aggressive cam as I was installing with a 4 speed so the idle rpms were less of a concern to me.
I had originally planned on using a 4bbl carb until I acquired an all original 66 Tripower that I thought would be a better wow factor when the hood was open. I thought the tripower was all good to bolt on and go.
After talking with Mike Wasson, and telling him of the engine configuration, he advised me that the stock 66 tripower would need to be modified to run correctly with my engine configuration. I was advised by Mike that I would need to modify the center carb idle circuit by drilling out the idle ports to his specs and shortening the idle spring to his specs base on the cam I was using and the more aggressive idle that the engine has. I was also advised by Mike on jetting of the carbs, float setting on all carbs and sealing of the throttle plates on the front and rear carbs.

What compression do you think you are running?

Thanks

Greg


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How did that work out? I understand opening the idle tubes and idle bypass restrictors, but don't know what you mean by idle spring. Do you mean the power valve actuating rod spring? If it's too stiff, with a lumpy cam and low vacuum, the power valve will be open most of the time, resulting in the fuel/air mixture being too rich.

The stock power valve rod spring on a Tripower center carb is about 220 grams. I've found that, with a lumpy cam, about 170-170 grams of spring pressure works well with the stock power valve. .Cutting about five turns off the spring is a good start.

Sorry about the terminology - you are correct - it is the stock power valve spring on the center carb that I cut down - per Mike Wasson's advice.

I had all carbs apart on the desk in my office and set all float levels and jets per his specs as I had never worked on tripower carbs. He was spot on as the engine with the tripower installed at its break in - dynode at 423.7 hp with 412.1 ft lbs of torque @ 5400rpm.
That is its peek performance after all dyno runs with some timing and jetting tweaks on the rear carb.
I am very happy with it.

It has been several years since the break in and dyno session on the engine. It sounds about right that Mike Wasson had me remove 5 turns off of the power valve actuating rod spring.

I wanted 425hp and got 424hp on good pump gas. I promised my engine builder that I would avoid holiday fuel - so no holiday fuels for this engine.

OK so my tri power parts will be here tomorrow. I still havent pinned down what compression I will be running, or cam. Low 9s compression is what I am reading.

Any body else I am looking for some zip its not a show car.

Thanks Greg

This is good to hear- looks like I am going to be building a 400 for my 66 GTO. I have a few head options- 48, 62, and 6X off the TA 6.6 motor.

Which heads do you suggest?

I agree that stock-ish is probably the way to go.

If you’re starting a fresh engine build I’d choose one of the two high compression 400 heads (the #48s are good) and then use the piston dish to determine your final compression ratio.

Choose your compression ratio wisely. Your choice should take into consideration what fuel you have available, what type of transmission you plan to use (what torque converter if auto transmission), rear end gearing and what camshaft you plan to run. Put the pistons at or very close to zero deck and use a .039” to .045” head gasket.

Hard to go wrong with a conservative 9.3:1 compression ratio which should be easily and safely compatible with most 91-93 octane pump fuel. If you’re feeling a bit nostalgic running the tried and true 068 Tri-Power cam might be a good option.

I believe that is what the engine builder suggested- he echoed what others have said. Moderate compression/cam. The car is just going to be a driver so I’m not too worried about getting every last bit of power. I would like my wife to be able to drive it if she wants. The plan is to go with vintage air and the ‘65 Tri-Power I have.

2X B-man

Thanks!

I am running edelbrock performer heads on my 428 4bolt main [434] with 10:1 compression. I will get my cam specs tomorrow.

I am running a Ultradyne 288/296 with Johnson 951R lifters. The motor/heads are all balanced, ported and polished.