engine swap questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

fluffytx1 · 08-28-2002, 10:06 PM

I have a 68 GMC, I am finally retiring the old 351 v-6 (spun a main bearing) and going to a small block 350. I am have rebuilt the TH400 tranny and have ran into some snags. HELP!!!! 1) I have looked at some other trucks with a 350 and the stands that mount the engine are different than the ones in my truck. Do I need to swap? If so where can I find them? LMC does not carry them, and there are none of these in the salvage yards. Is there any years that will work? 2) II dont want to go back with factory exhaust manifolds. What headers will work? 3) That 351 was really heavy and I compared my front coil springs to a friends and mine appear to be larger than his. Should I change them? Has anyone ever done this swap before? If so is there any other problems I should prepare for?

Thanks Scott

Longhorn Man · 08-28-2002, 10:28 PM

I don't think you can use your engint towers, if there are none locally in your junk yards, I am sure some one on the parts board has a bunch in there garage and are willing to sell.
If you get the proper small block perches, and put it all where small block stuff goes, then any header designed for the truck will fit.
I recoment the hooker super comps, they cost a but, but you get what you pay for.
As for your springs, slap the engine in, and see what it looks like.

pickup6772 · 08-29-2002, 11:51 AM

RE CHECK THE WRECKING YARDS. THE SIX CYLINDER(STRAIGHT SIX), AND THE EIGHTS USED THE SAME FRAME , AND RUBBER MOUNTS. THE SIXES USED AN EXTENTION MOUNT BETWEEN THE RUBBER, AND THE ENGINE BLOCK. HOPE THIS HELPS YOU OUT

dmnall · 08-30-2002, 02:45 AM

The easiest solution and a great upgrade would be goto a junkyard and find a 73 - 79 Chevy 1/2 ton truck and Take the front suspension along w/ proportioning valve and use that with the newer style motor mounts!! Just make sure that the doner truck you are getting it off of had a V8 in it!! Easy swap and then you will get Disc Front brake!! Another question, is your frame Trailing Arm Rear or Leaf Spring ?? Well if it is leaf then pull the rear end from the Donor Truck and you will have 5 Lug all the way around as well as Disc plus you will have an updated motor mount for around $ 200 - $ 300 upgrade !!

bigblok · 08-30-2002, 12:09 PM

I bought nos stands for big block installation in my 72 from chevyduty.com. I've also purchased other items from them. check out their free catalog.

08-28-2002, 10:06 PM	#1
fluffytx1 Registered User Join Date: Feb 2002 Location: point blank Posts: 113	engine swap questions I have a 68 GMC, I am finally retiring the old 351 v-6 (spun a main bearing) and going to a small block 350. I am have rebuilt the TH400 tranny and have ran into some snags. HELP!!!! 1) I have looked at some other trucks with a 350 and the stands that mount the engine are different than the ones in my truck. Do I need to swap? If so where can I find them? LMC does not carry them, and there are none of these in the salvage yards. Is there any years that will work? 2) II dont want to go back with factory exhaust manifolds. What headers will work? 3) That 351 was really heavy and I compared my front coil springs to a friends and mine appear to be larger than his. Should I change them? Has anyone ever done this swap before? If so is there any other problems I should prepare for? Thanks Scott __________________ 1968 GMC CST long wide box http://groups.yahoo.com/group/67-72-collectors/

08-29-2002, 11:51 AM	#3
pickup6772 Registered User Join Date: Aug 2002 Location: MASTIC BEACH, long island, ny Posts: 362	ENGINE SWAP RE CHECK THE WRECKING YARDS. THE SIX CYLINDER(STRAIGHT SIX), AND THE EIGHTS USED THE SAME FRAME , AND RUBBER MOUNTS. THE SIXES USED AN EXTENTION MOUNT BETWEEN THE RUBBER, AND THE ENGINE BLOCK. HOPE THIS HELPS YOU OUT

08-30-2002, 02:45 AM	#4
dmnall Registered User Join Date: Apr 2001 Location: Goleta, CA Posts: 505	The easiest solution and a great upgrade would be goto a junkyard and find a 73 - 79 Chevy 1/2 ton truck and Take the front suspension along w/ proportioning valve and use that with the newer style motor mounts!! Just make sure that the doner truck you are getting it off of had a V8 in it!! Easy swap and then you will get Disc Front brake!! Another question, is your frame Trailing Arm Rear or Leaf Spring ?? Well if it is leaf then pull the rear end from the Donor Truck and you will have 5 Lug all the way around as well as Disc plus you will have an updated motor mount for around $ 200 - $ 300 upgrade !! __________________ 1968 C10 Truck LWB Fleetside 1968 C10 Truck SWB Stepside 1994 K2500 Ext Cab Fleetside 2008 Honda Civic Si lease

08-30-2002, 12:09 PM	#5
bigblok Registered User Join Date: May 2001 Location: bangor,pa usa Posts: 29	engine swaps I bought nos stands for big block installation in my 72 from chevyduty.com. I've also purchased other items from them. check out their free catalog. __________________ 72 C10 475HP 402BBC Yes, it's fun, but gas ain't cheap!

08-28-2002, 10:28 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	I don't think you can use your engint towers, if there are none locally in your junk yards, I am sure some one on the parts board has a bunch in there garage and are willing to sell. If you get the proper small block perches, and put it all where small block stuff goes, then any header designed for the truck will fit. I recoment the hooker super comps, they cost a but, but you get what you pay for. As for your springs, slap the engine in, and see what it looks like.



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