Questions on doing an I6 to V8 swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jfw432 · 01-02-2017, 07:39 PM

I've read a lot about how easy swapping a V8 into a vehicle with an I6 but I've never really seen a list of what's actually required. So before I even look over the edge of the cliff, I'd like to know what's really involved. This is a 250 I6 with an auto tranny (2wd longbed) so my understanding is that the engine mounts and tranny stay right where they are and the new engine bolts right up.

Here's what I know I'll need:
engine, intake manifold, carb, exhaust headers, water pump, distributor and wires

Do I need these or just pull them off the I6?
fuel pump, radiator, radiator hoses

Alternators and power steering pumps are fairly cheap but I've got a welder if a bracket needs to be made. I've also got a 2.5" dia Flowmaster 50 so I'm thinking I'll need another one for dual exhaust unless the headers together to form one outlet.

What am I missing?

barry1982 · 01-04-2017, 03:20 PM

I have done (2) six - eight conversions. In my opinion, your best bet is to pickup a cheap V-8 truck with a blown tranny /diff and strip everything you need for your conversion. V-8's typically have a bigger Rad than a 6, and a different plastic shroud. Your alternator will interchange, but pretty sure rad hoses are different. If I recall, your six starter should bolt up to the V-8.

bigblock73 · 01-04-2017, 08:29 PM

Engine frame stands are the same, but you will need to move from the "6" position to "8" position. The different set of holes are stamped 6 and 8.

cheap · 01-05-2017, 11:56 AM

well, after you pull the inline 6 you'll have to put the crossmember motor mounts onto the other holes in the crossmember. The fuel pump on the inline has a longer arm, so it will not work. The heater hoses typically remain the same. The inline 6 radiator with a shroud and a 6 blade fan works for me, it never gets hot. But without a shroud and with a 4 blade fan I'm not sure. One of my rad hoses was able to work with slight modification, but I don't remember which one it was. Alternator and power steering pump are the same, but the bracketry is very different. Your engine will bolt to your transmission the same. I've sone this swap recently, so if you need more help I can try and assist

01-02-2017, 07:39 PM	#1
jfw432 Registered User Join Date: Nov 2014 Location: Lizella Posts: 41	Questions on doing an I6 to V8 swap I've read a lot about how easy swapping a V8 into a vehicle with an I6 but I've never really seen a list of what's actually required. So before I even look over the edge of the cliff, I'd like to know what's really involved. This is a 250 I6 with an auto tranny (2wd longbed) so my understanding is that the engine mounts and tranny stay right where they are and the new engine bolts right up. Here's what I know I'll need: engine, intake manifold, carb, exhaust headers, water pump, distributor and wires Do I need these or just pull them off the I6? fuel pump, radiator, radiator hoses Alternators and power steering pumps are fairly cheap but I've got a welder if a bracket needs to be made. I've also got a 2.5" dia Flowmaster 50 so I'm thinking I'll need another one for dual exhaust unless the headers together to form one outlet. What am I missing? Last edited by jfw432; 01-02-2017 at 07:45 PM.

01-04-2017, 03:20 PM	#2
barry1982 Registered User Join Date: Oct 2015 Location: Waskatenau, Alberta Posts: 259	Re: Questions on doing an I6 to V8 swap I have done (2) six - eight conversions. In my opinion, your best bet is to pickup a cheap V-8 truck with a blown tranny /diff and strip everything you need for your conversion. V-8's typically have a bigger Rad than a 6, and a different plastic shroud. Your alternator will interchange, but pretty sure rad hoses are different. If I recall, your six starter should bolt up to the V-8.

01-04-2017, 08:29 PM	#3
bigblock73 yeller Join Date: Oct 2001 Location: Twin Cities Posts: 13,826	Re: Questions on doing an I6 to V8 swap Engine frame stands are the same, but you will need to move from the "6" position to "8" position. The different set of holes are stamped 6 and 8. __________________ Jeff 73-87.com 73-87.com Facebook page 73-87 cab corner 6x9 speaker brackets for sale 67-72 cab corner speaker brackets for sale 47-54 cab corner speaker brackets for sale

01-05-2017, 11:56 AM	#4
cheap Registered User Join Date: Jul 2015 Location: earth Posts: 99	Re: Questions on doing an I6 to V8 swap well, after you pull the inline 6 you'll have to put the crossmember motor mounts onto the other holes in the crossmember. The fuel pump on the inline has a longer arm, so it will not work. The heater hoses typically remain the same. The inline 6 radiator with a shroud and a 6 blade fan works for me, it never gets hot. But without a shroud and with a 4 blade fan I'm not sure. One of my rad hoses was able to work with slight modification, but I don't remember which one it was. Alternator and power steering pump are the same, but the bracketry is very different. Your engine will bolt to your transmission the same. I've sone this swap recently, so if you need more help I can try and assist



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