Big Block Swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

CanadaDewey · 12-08-2006, 07:04 PM

Can anyone give me feedback on installing a Big Block in a 72 4x4 4speed. I have heard horror stories about doing this, even though it won't stop me. I see a lot off big blocks in your trucks so there must be a lot of knowledge out there.

Thanks

1969k10stepside · 12-08-2006, 07:06 PM

If its going in a 4x4 you will run into clearance issues and a body lift is the easiest way to fix that problem.

Jtrux · 12-08-2006, 07:38 PM

I dropped a 396 in my blazer and then proceeded to pull it back out. First, you have to run exhaust manifolds unless you can find headers, cuz I couldn't. The linkage has to be modified for all the headers I found. Second, the valve covers (even the really low stock ones) will touch the firewall. Solution, scoot drivetrain forward and run electric fans (if your not already) or bust out the BFH. If you put a HEI distibutor (I have the MSD one) it's really tight and you cant set a distubutor in without pulling cap and rotor and even then it's tight. Keep in mind I absolutely hate body mounts so I did everything possible to not have to resort to that. One thing for sure is that it looks really good under the hood, definitely fills any gap the small block left. Oh, if I was really dedicated i'd run a electric fuel pump because the mechanical one sits really close to the frame and wouldn't be any fun to try to change out if it goes out. Hope this helps, i'm not trying to talke you out of it even though it sounds like it but for me it was just too much work.

**Yukon Jack** · 12-09-2006, 10:51 AM

Jump over to the 4x4 section and also check out the link in my sig to my website. I put a bbc in my 69 K20 and have lots of info on my website about my install. You will find some people have to do very minor to no mods to put the bbc in, others like me have major firewall issues.

Moving the engine forward increases your front driveshaft angle, but if I were to do my swap over, I would go that route or I might consider making a custom engine crossmember and dropping the engine and drivetrain down a bit.

If you do the swap, keep us posted.

12-08-2006, 07:04 PM	#1
CanadaDewey Registered User Join Date: Dec 2006 Location: Medicine Hat, Alberta Canada Posts: 1	Big Block Swap Can anyone give me feedback on installing a Big Block in a 72 4x4 4speed. I have heard horror stories about doing this, even though it won't stop me. I see a lot off big blocks in your trucks so there must be a lot of knowledge out there. Thanks

12-08-2006, 07:06 PM	#2
1969k10stepside Registered User Join Date: Mar 2006 Location: USA Posts: 21,020	Re: Big Block Swap If its going in a 4x4 you will run into clearance issues and a body lift is the easiest way to fix that problem.

12-08-2006, 07:38 PM	#3
Jtrux I'm a poor spectator Join Date: Aug 2006 Location: San Antonio, Tx Posts: 2,287	Re: Big Block Swap I dropped a 396 in my blazer and then proceeded to pull it back out. First, you have to run exhaust manifolds unless you can find headers, cuz I couldn't. The linkage has to be modified for all the headers I found. Second, the valve covers (even the really low stock ones) will touch the firewall. Solution, scoot drivetrain forward and run electric fans (if your not already) or bust out the BFH. If you put a HEI distibutor (I have the MSD one) it's really tight and you cant set a distubutor in without pulling cap and rotor and even then it's tight. Keep in mind I absolutely hate body mounts so I did everything possible to not have to resort to that. One thing for sure is that it looks really good under the hood, definitely fills any gap the small block left. Oh, if I was really dedicated i'd run a electric fuel pump because the mechanical one sits really close to the frame and wouldn't be any fun to try to change out if it goes out. Hope this helps, i'm not trying to talke you out of it even though it sounds like it but for me it was just too much work. __________________ 2006 Jeep Unlimited IMPACT ORANGE 1993 Chevy 2500 4x4 ExCab LWB 454/NV4500 Tow rig 1977 Ford F100 2x4 LWB 1st truck I owned, still have it!!! 1979 Ford F150 4x4 SWB Built Ford Tough!!! 1971 Chevy Blazer 350 / SM465 / NP205 UNDER CONSTRUCTION Soon to have a LQ4 6.0!!!

12-09-2006, 10:51 AM	#4
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	Re: Big Block Swap Jump over to the 4x4 section and also check out the link in my sig to my website. I put a bbc in my 69 K20 and have lots of info on my website about my install. You will find some people have to do very minor to no mods to put the bbc in, others like me have major firewall issues. Moving the engine forward increases your front driveshaft angle, but if I were to do my swap over, I would go that route or I might consider making a custom engine crossmember and dropping the engine and drivetrain down a bit. If you do the swap, keep us posted. __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.