Exhaust Manifolds

[FluoFerret]

Hello!
I am looking to install a new exhaust system on my 78 Lemans, and I need some help, as my thoughts are stuck and I can't make up my mind. Here's what I am stuck with:

Engine is a "mild performance" 350cui Chevy Small Block with a 600cfm Edelbrock Carb.

Options for the exhaust system:

Headers (full length): no chance. on the passenger side, not a single set I bought fit the chassis. they always touched. shimming the engine or trying different engine mounts didn't help either. also: none have thick tubes to keep the heat within and i don't want to wrap them.

Headers (shorties): a good solution IF the headers go imediately downwards at the rear cylinder. why I don't like the idea: most of the time the sparkplugs are difficult to reach. also: none have thick tubes to keep the heat within and i don't want to wrap them.

Log Manifolds: good access to the spark plugs, they keep the heat inside, but not a very good exhaust flow.

Ram Manifolds: better exhaustflow, keep the heat inside, but no idea if they will fit past the frame below the engine. Has anybody ever done this here on a 78 G-Body without modifying the chassis?

Modified Log Manifolds: (as made by BRZEZINSKI Racing Products) Improved exhaust flow over stock manifolds but very expensive. Does anybody have any experience with their products?

Any advice to get me un-stuck is most welcome!

 

[TURNA]

Welcome to the site.






Chevy in a Pontiac.........................................................Blah!!!!!



Put a set of shorties on it if it just a crustier

 

[FluoFerret]

Welcome to the site.

Thanks

Chevy in a Pontiac.........................................................Blah!!!!!

Was the fastest, available upgrade after killing the Buick V6 and the TH200C

Put a set of shorties on it if it just a crustier

Any brand or model you would recommend in particular? I wish for tubes with thick walls and thick flanges

 

[TURNA]

99% of headers are 16 gauge.

For the shorties I used Hedman in the past and would use them again.

 

[pontiacgp]

Was the fastest, available upgrade after killing the Buick V6 and the TH200C

sounds like it was a planned annihilation ....

 

[FluoFerret]

sounds like it was a planned annihilation ....

Not really. It was a premature death caused by european traffic habits.
You see, generally speaking, in the US people tend to drive with a little more care and foresight.
As a good example among many: if the light turns red and you're still half a mile away, you let the car roll out and stop. And as soon as it turns green again, you resume your drive in a quite relaxed way. Me and my fellow europeans though, we go full throttle up to the point where we have to hit the brakes hard in order to stop at the intersection. At the green phase, if you're not imediately gone from your position as soon as the green light went on, those behind you will honk until your tympanic membrane is destroyed

This kind of driving routine doesn't work well for a midsize US car with a "weak" engine/transmission. After 500km of daily commute during rush-hour, my transmission started to act funny in third gear, and while accelerating away at the next intersection in our traditional style, the engine choked followed by a big "CLUNK" and the ride was over. Engine and transmission kaputt

 

[TURNA]

AHHHHH your on the other side of the pond .....I can see why a Chevy engine was a good choice for you then.

 

[pagrunt]

Welcome & here is what I'm using on my '81 Monte Carlo, set of mid '70's manifolds (about '76-ish). If you still using a stock single exit exhaust you'll need a custom Y pipe. Running true duals use Flowmaster's down pipe kit for '64-'81 A & F bodies. For headers I'd look into the Heddman 61318 standard headers or 68318 Elite headers. Ram horns won't work due to them being center dumps & won't clear the frame.

 

[Doug213xrj]

Hey, Welcome from West Michigan. I agree , If you don't like headers go with the stock manifolds as the photos show above. I installed headman hedders #68310 in 2003. Still in and in great shape. here's the problem I have with them. When using the factory starter I have to remove the passenger side header from the engine and the header from the exhaust the remove the starter. I installed Flowtech #31104FLT on the 78 El Camino. These are a great ceramic coated header for the price. I haven't had any problems with them . these Flowtech header are a true long tube header. I can remove the factory starter and use the big oil filter.

Doug.

 

[FluoFerret]

AHHHHH your on the other side of the pond .....I can see why a Chevy engine was a good choice for you then.

Yup, I love american cars from before the 80's, but getting parts like complete engines is almost impossible. crate engines are the only choice, but duties push the prices often beyond 10.000€, even if the engine + shipping only is around 5.000$. So a GM Performance block was the easiest and less expensive way for me to go (i was still at university back then). I WISH for the US and the EU to put their differences away and drop all duties on wares exchanged between our two continents!

Welcome & here is what I'm using on my '81 Monte Carlo, set of mid '70's manifolds (about '76-ish). If you still using a stock single exit exhaust you'll need a custom Y pipe. Running true duals use Flowmaster's down pipe kit for '64-'81 A & F bodies. For headers I'd look into the Heddman 61318 standard headers or 68318 Elite headers. Ram horns won't work due to them being center dumps & won't clear the frame.

Thank you for your answer and the pictures! I dumped the original exhaust system and have dual sidepipes (Patriot) without H-pipe, but I might go back to a full exhaust system going out at the rear. Is it true that original manifolds with "standart" engines tend to perform a little better for low-end torque?

Hey, Welcome from West Michigan. I agree , If you don't like headers go with the stock manifolds as the photos show above. I installed headman hedders #68310 in 2003. Still in and in great shape. here's the problem I have with them. When using the factory starter I have to remove the passenger side header from the engine and the header from the exhaust the remove the starter. I installed Flowtech #31104FLT on the 78 El Camino. These are a great ceramic coated header for the price. I haven't had any problems with them . these Flowtech header are a true long tube header. I can remove the factory starter and use the big oil filter.

Doug

Hey Doug, thank you for your reply ^^ I currently have the headmans #68310 installed. They did not clear the frame on the passenger side so I had to re-weld a tube and flatten the outer side of it with a hammer For the stock manifolds I am still undecided if I should take optimized one like those offered by BRZEZINSKI Racing Products or if I should buy new one from OPGI. Both are expensive, but the quality seems to be way above these low cost parts from the competition. Any suggestions here?