Fitment of the LMC exhaust on a BB pickup?

[MrC1]

LMC's 2.25" mandrel bent kit only lists 273-350 engines. Anybody know if there's a difference with big block engined trucks? Mine's a 402, but I don't see why this kit wouldn't work.

[GMCPaul]

It could be modified to fit I would think but shouldn't be a direct bolt up I would think if your using stock exhaust manifolds, if using headers no problem, myself I like 2.5" pipe or bigger on a big block though.
GMCPaul

[MrC1]

Thanks for the reply.

I plan to go with headers, so that's not a problem. I think my question has to do with exhaust hanger mounting points and pipe routing on the big block trucks vs the SB ones. Now that I type it I can see that it's probably a dumb question! All the mounted stuff should be the same!

The pipes are only 2.25", but are mandrel bent. They will flow better than 2.5" pipe that's been crimp-bent and is plenty for a 402 turning no more than 5200 RPM. If I had a 454 I'd probably agree with you on that unless it wasn't turning over about 4800, like some trucks.

I also don't want it to be that loud, so 2.25" should work great!

[Dano69c10]

The same company that sells the SBC exhaust system in LMC, sells an exhaust system for big blocks. I found them in the JC Whitney catalog. I installed on a C20 and they went in no problem.
Dano

[MrC1]

I went to JC Whitney's site and found the kits, but there's no mention of SB or BB. Actually, there's no mention of how well the kits fit and if they offer the fatory exit locations, etc. Looks like generic kits that you cut to fit. This can;t be what you're referring to!

[Dano69c10]

Actually the company is Heartthrob Exhaust, here's the link.
http://www.heartthrobexhaustinc.com/...ddualkits.html
I used the 73-87 big block kit. The truck had a th-400. Maybe give them a call and talk to their tech department.

[MrC1]

Thanks!

Unfortunately this site doesn;t list anything for our trucks with headers, nor does it list ANYTHING for our trucks with a big block. These are all SB systems.

There are a few listed as 283-400 SB and then there are a few listed as 283-400. If you click on one of those, the instructions say "Small Block".

Argh!

[MrC1]

I just talked to their tech support and found the following:

They do not have ANY header kits for 67-72 Chevy pickups.

They do not have ANY BB manifold kits for 67-72 Chevy pickups.

He suggested to go with their small block manifold kit and just cut and massage it to fit.

Price without mufflers is $148.22. I expected a bit cheaper since LMC has the same kit WITH muffs for $169. Very strange.