it seems that the old corvette ram horn manifolds are the best but what are other good options out there?  And where can you get them?

It is time for new exhaust pipe and mufflers (mine are rusting through) and I might as well upgrade if I can.

CD

dirtmopar44 wrote on 03/12/13 at 3:03pm:


I don't think the center dumps fit in a nova notching the crossmember and moving the engine back (which is supposed to be illegal). I will have to take a closer look.  The price is certainly right.

That casting number list is nice.  I wish they had some info on the newer castings (the ones you might actually find in a junk yard).


CD

years ago i read an article from berzinski. it said that from the factory, the standered log style manifolds are the best, but after they get done altering them, the centerdump style were better. always had good luck with the log type.

Here is what Brzizinski says http://www.castheads.com/faqs_exhaust_manifolds.php

its MONKEY see Monkey DO whatever the guy wins alot with EVERYONE will ASSUME they need them! my junk yard specials do fine

Dorman reproduces the 1962-1967 corvette center dump with 2 1/2" dump.
I'm using them on a 75 nova, but you have to notch the cross member frame. Didn't move engine location.

So after a bunch of research (i.e. looking on the internet and asking people questions) I have come to a conclusion.... I don't know what I am going to do yet.

Everyone seems to agree that the 2-1/2" corvette ramhorns are the best but they may not be legal for my car at Perris and I am not a big fan of notching the crossmember.

I have heard conflicting reports on the late model truck manifolds.  Some say they are the best and others (including Brzezinski) say the runners are too small.

I have heard the LT1 manifolds are good on a mild engine like mine but I have that they are also too small and aren't good above 5500 rpm.

My pre-smog logs are still in the running.

I do appreciate all the input and would like to hear more opinions.

CD

I did some measuring on the manifolds I have at home last night.

The pre-smog logs I am currently using have a 2" outlet.

The non-corvette ram horn manifolds I have look like they might actually fit because the outlet is angled toward the back the the vehicle.  They have a 1.875" outlet and inlet ports (that interface with the cyl head) approximately .08" - .10" smaller than the logs.

The truck manifolds I have, have a 2.125" out let and inlet ports that are the same size my logs.  Unfortunately, I found they were cracked when I removed the heat shields.  And I didn't pay close enough attention what vehicle I took them off of (it was white but not sure that helps).

My friend has a 1999 chevy 4x4.  The exhuast pipe diameter just after the exhaust is 1.875".  So not all truck manifolds are the same.

Although the corvette ram horns with 2-1/2" outlet are readily available through dorman for a reasonable price I have decided that notching the crossmember (I'd have to cut away about 1/3 of the crossmember) is not something I want to do.  

I am going to head to the junk yard this weekend.  If I can find  more of the truck manifolds that I have (uncracked) I will go with those, otherwise I am sticking with the logs.

CD

Here's what I have gathered from other places on the Internet:

Corvette 2.5" center dumps are very good.  The angled ones you have are probably off a 60s/70s truck.

LT1 manifolds are good for flow, but the ports don't line up with older Chevy heads.  There are a couple places online that make an adapter from old heads to LT1 manifolds to smooth everything out to line up correctly, but I imagine they are probably illegal.

Late 80s/early 90s truck manifolds are supposed to be pretty good as well.  '99 would be into Vortec heads, I don't know how those exhaust manifolds line up compared to older heads.

There are some 70s log style manifolds that have spreader bars cast into them that make them much easier to install, those are the kind I ran on my American stock last.