I'm going to be doing the 305 to 350 conversion & I need to know if the Stock manifolds & exhuast will work or not & what if anything needs to be changed.

I have an 85 Iroc Z-28, stock, going to an 85 350 4 bolt main, bored 60 over, flat top pistons, ISKY cam (dont have all the specs on it), 194 heads, it has TPI
My smog pump is dead already, im debating what to do aobut it, I do want it to pass emissions & such (even thou i hate them)
thanxs for any advice & suggestions.

 

Yes, the old stuff will bolt up fine. But this is a perfect time to slap some headers on.

 

you are correct about the time. what about emmisions? does it all bolt up? what about this Y pipe i have read about ?
thanxs

 

Actually great time to upgrade the entire exhaust. Get Hooker 2055 headers for '86-'91 TPI single cat (or similar emissions-legal headers), cat and cat-back for the same application. It will all bolt together, have a nice plate that says it's CARB-certified, and will flow sooooo much better than that stock 305 system.

 

Yea with the engine it will be a great time to do the entire exhaust system. You can put on the headers while putting the 350 in and save yourself the hassle later on when the engine is in.

 

Hey Five7
I've read many of your posts & you are helpful & seem to know what the hell your talking about, but I want to make sure those are the correct part numbers as I have an 85 (I know there shouldn't be much difference between 85 & 86.
Thanks, just making sure
I've done conversions work before & it can be a nightmare, just trying to avoid any potential problems
Thanxs

 

They are the correct part numbers for my '82 with an '86 engine, for that matter.

The year doesn't make any difference as far as fitting onto the engine or into the chassis goes. The exhaust size and joint arrangements changed over the years, and that's why they list systems for particular years (so the piece you're buying will fit to the rest of your exhaust). But, if you get the 2055 headers, and cat and cat-back designed for '86-'91 TPI single cat, then it will all bolt up to your engine, chassis, and each other.

 

any suggestions on the cat & cat back system (what exactly is the cat back?) and or muffler ? I've heard the flowmaster is a good choice
Thanks again
Hey five, i did not mean any disrespect earlier, sorry if it came across that way, The work im going to be doing is an emergency transplant (motor dying REALY quick) & of course the money tree is out of season, so I have pretty limited funds to work with currently.
Thank you

 

"Cat-back" is everything in back of the catalytic converter - intermediate pipe, muffler, and exhaust pipes. Sometimes also referred to as after-cat.

Flowmaster, Hooker, Dynamax, all seem to be good systems. I picked mine up from JC Whitney, then ordered a Flowmaster muffler only from Summit and tossed the muffler that came with the system. Slightly less expensive than a full Flowmaster system.

That tree never seems to be in season at the right time, does it?

(BTW, no disrespect detected. Glad to help - assuming it is helpful.)

 

yes it was
I managed a swap this weekend. Trading a 360 Block (old Dodge) to have a guy put in al new exhaust from the headers back, he works in a muffler shop. so im going without the cat, should i still get the 2055 headers then, as I recal they had the smog lines, im pulling my smog pump it siezed up a a long time ago. im going to clean up my engine compartment some & get rid of the excess garbage, will I still need the charcol canister? not that its even hooked up, I had a shop install a fuel pump 2 years ago & they crossed some fuel lines in the tank I had gas pouring out of the charcoal canister, so i had to block it off. I have never been able to find any schematics on what goes where, if you do I'd appreciate the pointer in the right direction, to get it fixed
Im getting ready to pull the motor & tranny in few weeks & want to do do it all at once
thanxs again

 

If that "headers back" offer includes a y-pipe, then you might want to consider the 2460 headers, which don't have A.I.R. or y-pipe. You can have him make a pipe that connects the two sides and goes directly to the cat-back connection point.

The charcoal cansister provides the venting of the gas tank, so it's a good idea to have it at least partially hooked up.