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Cutlass exhaust manifolds

3K views 9 replies 9 participants last post by  351fairlane 
#1 ·
Hi

I recently picked up and exhaust for my Cutlass. It is a dual exhaust but my passenger side exhaust manifold has a crossover pipe that connects to the drivers side exhaust manifold and I just have 1 pipe running back.

I was wondering if I could goto a local junk yard and pickup a different exhaust manifold with out the crossover pipe. So I can run a exhaust pipe for each exhaust manifold instead of 1 exhaust pipe.

I remember seeing a 1985 Cutlass Supreme with a v-8 with the manifold I need but I dont know if it is a 305 cutlass or a 307. Does it matter which if it is a close year? Also is there something I can look for to find out if the car is a 307 or 305, like a vin number or something?

Please help me out.

Thanks, Chris
 
#2 ·
ChrisMiddleron said:
Hi

I recently picked up and exhaust for my Cutlass. It is a dual exhaust but my passenger side exhaust manifold has a crossover pipe that connects to the drivers side exhaust manifold and I just have 1 pipe running back.

I was wondering if I could goto a local junk yard and pickup a different exhaust manifold with out the crossover pipe. So I can run a exhaust pipe for each exhaust manifold instead of 1 exhaust pipe.

I remember seeing a 1985 Cutlass Supreme with a v-8 with the manifold I need but I dont know if it is a 305 cutlass or a 307. Does it matter which if it is a close year? Also is there something I can look for to find out if the car is a 307 or 305, like a vin number or something?

Please help me out.

Thanks, Chris
*******
305 and 307 chevys are the same manifolds. If it is an olds engine, the manifold is different from chevy.

yep VIN
 
#4 ·
ChrisMiddleron said:
Hi

I recently picked up and exhaust for my Cutlass. It is a dual exhaust but my passenger side exhaust manifold has a crossover pipe that connects to the drivers side exhaust manifold and I just have 1 pipe running back., Chris
You remove the crossover pipe, thats where the duals are
going to connect, then find a freeze plug and install it where
the single exhaust pipe hooks up, using the flange off the
single to keep it in place...
 
#6 ·
It sounds like you have a "real" Olds engine. They used a passenger side exhaust manifold that had two outlets. One connected by a u-shaped pipe to the driver's side manifold. The other was the exhaust to the muffler.

The quick and dirty way to fix this is to take down the crossover pipe, cut it off about 3 inches from the passenger manifold, beat the cut and flat, and weld it shut. Of course it now acts as a water trap and tends to rust out first.

You might find a true dual olds engine in the salvage yard and get a proper manifold. I think I would look into headers.

You need to verify if you have an Olds 307 or a Chevy 307. If I remember correctly, the Olds has a fill tube up front for the oil with a metal cap. The Chevy fills in the valve cover.
 
#7 ·
maybe

the olds 307 would be a big block and the manifolds is totaly different....if it is a chev the manifold should have one opening on either side .
all i ever done was cut the crossover off above the join and shorten the other side then run pipes from there. i have a 84 cutlas and that is what i done...it came with stock 305
 
#9 ·
Shouldn't the downpipes unbolt? i thought the collecter was bolted onto the manifold. And if thats the case, unbolt it, cut the Y and use clamps(if you dont have a welder) to attatch two new pipes to the collectors. I did the same thing with my caddy. I couldn't fit headers in the engine bay. I cut the y pipe up and put two side pipes on.
 
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