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6.6 Pontiac tri power

jaloi

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OK,For personal reasons,I've chosen a Pontiac 400 with an original tri power setup to put in my 75 ventura(had a 67 GTO w/tri power once).All is well until I come to the exhaust.What to use for headers..... anyone know of any that would work? I know.... can't so anything the easy way...:D
 

jaloi

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Awesome,thank you much! Now for motor mounts,lol. Probably run the Firebird engine mounts and the Ventura frame mounts.It just bugs me that they didn't run a Pontiac engine.It deserves a Pontiac power plant,darn it! Thanks again!
 

cammerjeff

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Belleville MI
I am not sure about Motor Mounts, I thought you could use the earlier 73/74 Pontiac 350 Motor Mounts in the 75-77 Ventura's, But I could be wrong on that. I have never owned or worked on a 75 or later Ventura, But I have seen a few with Pontiac V-8 Engines installed in them. I will ask a few questions and get back with you.
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jaloi

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That'd be great.Sure would appreciate it! I heard 67 or 68 Firebird mounts,but rather be a little more sure before I go buying them.Thanks!
 

cammerjeff

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Belleville MI
This is the initial response I received from the Guy that did this same conversion on a Local 75 Ventura. He did the engine conversion about 10 years ago, and they added the tri Power 2 years ago. If I hear anything else I will pass it on.

I asked

I was asked what Motor mounts are needed to put a Pontiac V-8 in a 75-77 Ventura? I am thinking the 73-74 Ventura GTO frame mounts and Motor mounts would work. Is that correct?

Bill's Response

Should be but there are some frame changes because the Pontiac motor was never going to be installed again. I have seen the F style adapter mount used to install the early motor in a second/third gen fbird used in concert with the chev frame mount made to work in this type of app. but think the may be some minor fore and aft location issues with headers. I cant remember which we used on Craig's car. I will check and let you know

Also I have verified that 67-69 Firebird V-8 mounts are interchangeable with 73-74 Ventura V-8 mounts.

Also what year timing chain cover do you have for you engine? When the recast the Pontiac Timing cover in the early 70's they took the Tri-power water neck dimple out of the cover. For some reason all the repo covers I have seen also do not have the clearance for the Tri power water neck. So some modification to the water neck may be needed if you plan to run a 69 or later timing cover.
 

jaloi

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That sounds great.Any info I can squirrel away on it is much appreciated.As for the timing cover,I hadn't given that any thought.I never noticed on my GTO.I'm sure there's a way to get around it though.If not then I'll be looking for an original timing cover as well.What ever it takes! Pretty stoked that someone else has already done this swap! Can't think of a more appropriate engine for it.Thanks again for all the help! Sounds like just the guy I've been looking for!
 

cammerjeff

Member
526
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Belleville MI
I have been Told that you can Grind a little material from both the Water Neck and the timing cover to get the Water neck to fit. But I would not grind on the timing cover myself. I would Cut and weld up just the water neck for Clearance.

Here is a link that shows the difference in timing covers,

http://www.wallaceracing.com/timing-cover-numbers.html

you can see the indentation for the tri-power water neck on the inside left of the 1968 cover and it missing on the 1970-76 cover. (behind the water Pump)


Anouther Issue I forgot about is exhaust crossover ports on the later heads
(72 to 79) are taller, and the earlier intake manifolds will not cover the top of the cross over, and you will have hot exhaust gas leaking out. I have seen the top part of the passeges filled with block filler to correct this issue.

Here is another link showing the crossover port differences

http://www.wallaceracing.com/intake-crossover.html
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jaloi

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Looks like there's some parts I'll need to get ahold of.I've seen the tri power timing covers for sale.Not cheap,but they can be had.A pre 72 set of heads as well.Looks like if I want to do this right it's gonna be somewhat expensive and time consuming.Well,I guess if I want to do this right then that's what I'm up against.Got all winter! Thanks,man.You're help's been priceless!
 

cammerjeff

Member
526
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Belleville MI
This is the latest response I have from Bill

It would appear that the F style mount was used on CH's 77 Ventura. I can't reach the guy who did the actual job as he has moved to Texas and so far has not responded to voice mails.

But from everything he can find out it seems the F-body mounts will work.

Also if you plan on using the earlier Timing cover, make sure you get all the accessory brackets, Pulley's, and Harmonic Balancer for the year timing cover you get. I am not exactly sure what year the Harmonic Balancer style changed, I believe 67 & 68 are the same, and 64-66 will interchange but like I said I am not sure on what year parts will work together.
It is easier to just get all the parts from the same engine.
 
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