Pontiac Owners Club UK

I'm looking for some advice on weather to go for short or long tube headers. I'm aware that I'd probably have to get a mini or lt1 starter to make them fit.
Is there much difference between the two?

I'm aware ground clearance is an issue, at the moment with my stock exhaust the lowest point is my decat pipe with 5 1/4in ground clearance. the only real way of routing the y pipe, which I would have to make, is around either side of the trans pan and under the trans cross member. I held my claybar tub under the cross member, it measures just under 2 7/8in, giving 4in ground clearance.
I've added 2 pics, the side 'reinforceing' bits of the cross member are 1in. so what if I cut them off, just enough to have the pipe a little higher. then on the back side weld a L bracket that could bolt on the inner side of the frame to compensate for the loss of support? I've drawn the added L bracket red in my drawing.

Here's a spare cross member showing the reinforceing side bits:


and here is my proposed mod:


the long tube headers have 3in collectors and come with reducers, so if my y pipe was 2.5in, that could give 1/4in more clearance. the proposed mod nearly 1in, so I'd guess with that being the lowest point, I should loose max 1in clearance.

I also know that shortys are almost a bolt in. long tubes may require more work. I've read some people had to dent thiers to clear the engine cross member, but I'm sure I could grind/weld a V shape into it rather that damaging the headers.

Oh and I haven't tried using the scary looking welder under the stairs yet, so no idea how easy/hard/impossible it is to teach myself welding.

Is it worth trying longtubes, or should I just go shorty?
thanks.
RIchard

due to clearance issues and reduced ground clearance/fitting hassles I went for short tubes on mine (as did David) and they make a big difference
long tubes are better to a degree but in real terms for road use with an unmodified engine the gains are too small I felt but this is my personal opinion
welding is not too hard to master (practice on scrap metal first) especially on thicker metal like the cross member. and a reinforcing web opposite will work fine
long tubes were certainly more trouble and the oil cooler and switch are a problem as well as the starter

Would that be the oil pressure switch?
I don't have an oil cooler so that's one less thing to worry about.

I've got to repaint the engine bay this summer as there is rust appearing in places. plus the the engine and trans will have to come out to fix lots of leaks. the trans is leaking from the input shaft seal. it's always done it, but isn't just a little spot now, is getting worse. I've also got to remove the brake master cylinder as part of the rear disc conversion. So I figure, if I have to remove loads of stuff, might make long tubes possible.

More than happy with my shorty hooker headers, i did look at long tube ones when i started shopping around then read how much extra work was involved, and for a cruising / street car they didnt seem worth it. So them coupled to my stainless exhaust did make quite a difference in sound and how quick the car gets moving.

Mine follows the standard routing so no problems with it either, and the headers did indeed just drop in from the top, mine was made a lot easier to install because ive binned the AC and emissions crap so i had much better access, and i also had the heater box off too

Go for shorties

For the moment I'll be using the manifolds and y pipe from a 350 tpi. Haven't really got the money for headers and the 350 manifolds have a 1/4 inch bigger outlet, so should make a small difference. Only bit I'm missing is the y pipe as the one from the donor was too rusted.
The long tubes I was considering are discontinued as of a few months ago. So I'll be living with the small upgrade and getting some shorties when I rebuild/replace the engine when it dies.

the rest of the exhaust will be 2.5 inch with a hooker aero chamber muffler to replace my stock 2.25 inch twin resonator system

Currently I get 16 in vacuum at idle and about 11 at 3000rpm, indicating excessive back pressure. There's no dents etc, so that is either due to the resonators being clogged, or a 2.25 exhaust being rubbish.

so that'll be solved and should sound better too.