Rob_64-365

ok so I've gone thru all the numbers on my car, vin plate, trim tag, stamp pad, heads, carb, motor, ect, everything's in line, dated in the right time frame, it all lines up. So I didnt check the manifolds, just assumed they were the 2 1/2" that (I think ) come on the 365 horse motor, so I blasted and painted them and was putting them on, and I pull out the doughnut, and voila the 2 1/2 doughnut sure is alot bigger than my manifold diameter!! Not that big a deal, but what gives, is the 2" whats supposed to be on there, or at some point over the last 42 years did this system get changed over? Kind of irritating after hearing all the power loss with the 2" system, I think Ijust found the perfect excuse to change this system over hmmm headers, or stock 2 1/2 manifolds for xmas this year, from me, to me!!

BarryK

what's the number on them?

365hp manifolds should be:
LH: 3846563
RH: 3797902 unless you have AC than RH is: 3797942

ctjackster

also don't forget to use the little metal "sleeves" that should be on there already, inside of the "donuts"

for the 2 1/2 mani. that's Paragon pn 4094:



The 2 1/2 " exh donut is P pn 924

Rob_64-365

I didnt check my numbers last night, but I definitely have the 2" manifolds, which just stumps me. I'm putting it together as is, but for the 2 1/2" manifolds, and a whole new exhaust system, it's gonna be $12-$1500 for 2 1/2 all the way out like it's supposed to be. I just hope someone comes thru with manufacturing an exact copy of the real gm off road mufflers by the time I get around to replacing all of the exhaust system from the motor back. I gotta dig a little more and see if there are any issues with doing this?

wmf62

you can get repo 2-1/2" exh manifolds for less than $200, then have reducers fabricated to fit your present 2" system. then when you get the $$$, you'll already have the 2-1/2" manifolds. that's what i am going to do with my 62, sure won't hurt anything.....
Bill