Fitment of the LMC exhaust on a BB pickup? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

MrC1 · 04-10-2007, 11:43 AM

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** · 04-10-2007, 01:21 PM

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 · 04-10-2007, 03:24 PM

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 · 04-10-2007, 05:30 PM

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 · 04-10-2007, 09:21 PM

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 · 04-10-2007, 11:56 PM

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.

04-10-2007, 11:43 AM	#1
MrC1 Dork For Days Join Date: Aug 2005 Location: Dallas Posts: 407	Fitment of the LMC exhaust on a BB pickup? 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. __________________ 1972 C20, 402/700R4 - My first classic truck, bought in September 2005. 85% transformed from "Farm" to "Cool" status! 1970 Dodge Challenger 440, 4sp (my other toy) 12.67 @ 117 MPH, with a pathetic 2.022 60' 2007 Dodge Charger SRT-8 2008 Cadillac CTS All-American garage, baby!

04-10-2007, 01:21 PM	#2
GMCPaul Senior Member Join Date: Mar 2000 Location: Rockville,In. USA Posts: 3,721	Re: Fitment of the LMC exhaust on a BB pickup? 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 __________________ Secure Online Catalog for-GMCPauls Truck Parts Email- GMCPAULS@GMAIL.COM

04-10-2007, 03:24 PM	#3
MrC1 Dork For Days Join Date: Aug 2005 Location: Dallas Posts: 407	Re: Fitment of the LMC exhaust on a BB pickup? 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! __________________ 1972 C20, 402/700R4 - My first classic truck, bought in September 2005. 85% transformed from "Farm" to "Cool" status! 1970 Dodge Challenger 440, 4sp (my other toy) 12.67 @ 117 MPH, with a pathetic 2.022 60' 2007 Dodge Charger SRT-8 2008 Cadillac CTS All-American garage, baby!

04-10-2007, 05:30 PM	#4
Dano69c10 Senior Member Join Date: Jan 2005 Location: Ontario, Kali Posts: 2,427	Re: Fitment of the LMC exhaust on a BB pickup? 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 __________________ '69 Fleet It ain't yours, if you didn't build it!

04-10-2007, 09:21 PM	#5
MrC1 Dork For Days Join Date: Aug 2005 Location: Dallas Posts: 407	Re: Fitment of the LMC exhaust on a BB pickup? 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! __________________ 1972 C20, 402/700R4 - My first classic truck, bought in September 2005. 85% transformed from "Farm" to "Cool" status! 1970 Dodge Challenger 440, 4sp (my other toy) 12.67 @ 117 MPH, with a pathetic 2.022 60' 2007 Dodge Charger SRT-8 2008 Cadillac CTS All-American garage, baby!

04-10-2007, 11:56 PM	#6
Dano69c10 Senior Member Join Date: Jan 2005 Location: Ontario, Kali Posts: 2,427	Re: Fitment of the LMC exhaust on a BB pickup? 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. __________________ '69 Fleet It ain't yours, if you didn't build it! Last edited by Dano69c10; 04-11-2007 at 12:01 AM.



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