[Jon Salem]

Are all the bolt holes used when mounting pontiac 400 exhaust manifolds??

While replacing a warped 1971 pontiac 400 Lemans sport exhaust manifold, I noticed that it had only four bolt holes: two on the inside of the outer ports and two around the inner two ports. The used replacement manifold, which fits fine, has 2 extra holes on the outside of outer ports. The block has holes to match, but the picture in the factory manual does not show the bolts being used. To further add confusion, the maual states that the gasket can be hung on the outer bolts to ease installation, implying that they are used. Does anyone now the differnce in the manifold, and weather all bolts holed should be used?? I don't want to over constrain the manifold and break it!! Thanks

bluesjon@aol.com

[b-man]

In 1969 the 2 outermost holes were eliminated on most standard exhaust manifolds, instead of 6 there were only 4 bolts used.

If the replacement manifold has 6 bolt holes, by all means use all 6 if the head has all of the 6 holes drilled and tapped in it. It will still seal with only 4 bolts.

[Jon Salem]

Thanks much! Quite the video.

Any idea if Lemans Sports came with a "GTO option"? Someone mentioned that a GTO option existed. My Sport has the hood scoops and rubber nose, and when I bought the car in 1978 they were origional on the car, yet most sports have the chrome nose and no scoops....

[b-man]

.....but the T-41 option was available. This consisted of the GTO endura bumper, fenders and scooped hood. A nice inexpensive way when they were ordered new to dress up your car and give it a 'GTO look', but really never known as the 'GTO option' by the better informed Pontiac enthusiasts.

In '71 the GTO was a separate model with it's own GTO VIN#, but by '72 the GTO was no longer a model line and was just an option on the Lemans line.

Interesting T-41 thread:http://forums.maxperformanceinc.com/...ghlight=endura

[Jon Salem]

Thans again - you are the man. No wonder the video.

[Jon Salem]

What s the difference between a GTO and the Lemans Sport with the T-41 option? The Lemans has a 400/4BBL/dual exhaust..............

[b-man]

Originally Posted by Jon Salem

What s the difference between a GTO and the Lemans Sport with the T-41 option? The Lemans has a 400/4BBL/dual exhaust..............

I'm sure the GTO has a few added trim features that the Lemans didn't have.

I would suggest asking your question in the '70 -'72 GTO/Lemans forum for the best response.

[F ROCK]

i've got a gto clone made from a 71 lemans. not sure about the sport lemans but:
the gto has boxed lower controll arms w/ sway bar; different steering box; seats, interior door panels, instrument panel, heavier front sway bar, 15" wheels, different rear valance, and i think the endura nose lemans hasan egg crate type grille; while the goat has a cross hairs type grille. the vin starts with "242" on all 71 gto's, the lemans is 235.
yours sounds like a cool car. those are comanding a good buck in jersey. its worth more original.
mine was not a sport, came w/ 350/ 2bbl. was'nt worth much. we found a junk goat, and converted everything but the vin # to my lemans. have better/ more recent photos than this one...somewhere.

[Jon Salem]

Thanks for the info.

I bought it in 1978 with 60,000 miles and replaced most of the sheet metal while working in a body shop. I've been driving it since in good weather. The changes I remember making were putting on dual exhaust and a holly carb. It is idling poorly cold now, so the carb and valves may need some work. Is it worth rebuilding the Rodchester?

It does have the egg crate grille. Guess I got lucky with the factory 400/4bbl/convertible.

It s still fun to drive. Good to hear that original is OK. But I was thinking about some 15 x 7" rally wheels if I can find a set.

I'll have to figure out the insert-a-photo deal.

[b-man]

Originally Posted by Jon Salem

Thanks for the info.

I bought it in 1978 with 60,000 miles and replaced most of the sheet metal while working in a body shop. I've been driving it since in good weather. The changes I remember making were putting on dual exhaust and a holly carb. It is idling poorly cold now, so the carb and valves may need some work. Is it worth rebuilding the Rodchester?

It does have the egg crate grille. Guess I got lucky with the factory 400/4bbl/convertible.

It s still fun to drive. Good to hear that original is OK. But I was thinking about some 15 x 7" rally wheels if I can find a set.

I'll have to figure out the insert-a-photo deal.

Definitely have the Rochester Q-jet redone, better fuel economy than a Holley and just as much performance. Also keeps the car original, look up Cliff Ruggles for Q-jet work, he posts on the forums frequently giving advice and tips.

Posting photos isn't too difficult, ask how in the 'Test n tune' forum and you'll get help doing that.