[firechicken]

I considered 301 manifolds as well and the passenger side would work well. The problem on the F-body is where to run the downpipe on the drivers side. 455turbo routed his around the steering shaft and was obviously not an easy task. I'm sure he realizes the problem in this area. My car, however, is a 4-speed and the Z bar prevents this routing. The only ideal route I could see other than modifying the firewall was between the #5 and #7 cylinders by snaking the #7 exhaust tube to make room for it as noted in the above pic. The only other option is a very long pipe that crosses under the frame rail at some point which is unacceptable to me. A 301 manifold or any other for that matter would block this passage way.
I have 2 T-3's from Regal T-types which I'll probably use. I do have 1 turbo from a 301 car and if I can find another I will use them. In fact if anyone on the board has a decent one lying around I may be interested in swapping for Poncho parts or possibly purchasing.

[TTAJay]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Tom Vaught:
Some years ago a Pontiac Engineer named Skip McCully and I talked about using TWO of the
Pontiac 301 Turbo cast iron manifolds (one for each bank) on a 455 twin turbo deal he
was interested in.
...

If you could find two of the turbo manifolds you might save a lot of work on that plumbing.
...

Tom V. <HR></BLOCKQUOTE>

Though this isn't going to help firechicken with his setup I thought this info might be helpful to other people starting their own twin turbo project. I've got 2 passenger side Turbo 301 exhaust manifolds I'm planning on running for my twin turbo setup. On my '79 TA it looks like it clears the steering shaft. The only things these manifolds need to put on a 325-455 is to have the center exhaust bolt hold plugged/welded and to weld a cap over the bottom exhaust outlet.

One thing to look out for is that 95% of these turbo 301 exhaust manifolds are cracked. If you know a good welder that can weld cast iron then it isn't a problem.

I realize that these manifolds won't flow the same as a nice custom header but I'm just trying to keep it stupid simple. I can always just turn up the boost.

[455Turbo]

How about losing the Z-bar? You could use a hudraulic throwout bearing like this one from Howe Racing. It would take some effort to mount a master cylinder for it but it could free up some space. I took a look at my car and it looks like there's some room for it.

[firechicken]

Now there's something I didn't think of and yes that would make some space if there is room for a master cylinder. I am quite confident, however, that a 3" downpipe will fit quite nicely in the proposed location with much less hassle than changing to a hydraulic clutch and probably save $1000 as well

[Mo]

F/C You may want to try an anti-reversion cone on the center exhaust ports. It may help with keep exhaust out during overlap. Could also try it on front cylinder since the flow is in the opposit direction of the other three.

[Taff]

How about a pair of these? Looks like Pontiac were ahead of the game.

[firechicken]

Twin turbo Pontiac in 1961 Wow! I wish I had a pair of those collecting dust in my shop. Pontiac engineers never cease to amaze me.

[mikeb]

Yeah, I wish I had a set of those gathering dust too. As usual PMD engineers were way ahead of their time.

The design of the manifolds does give me some ideas on how to proceed on my own DIY manifolds whenever I save enough pennies to proceed in that direction.

[Tom Vaught]

You guys like those manifolds?

I had the only set in existance for a couple of years along with all of the other pieces.

Turbos, cross-ram, waste-gates, discharge pipes, etc.

I collected the stuff over many years and eventually sold it to Randy Williams hoping that
we would eventually put a twin turbo big car together.

Tom V.

ps it would not be that hard to duplicate those manifolds with weld-ls.

Tom V.