1970 454 Motor Swap
Thread Starter
Intermediate
Joined: Feb 2012
Posts: 31
Likes: 3
1970 454 Motor Swap
Hello All,
Just a generic question. I have a 1970 corvette with a non mtaching 350 motor. I would like to replace it with a 454 big block. Will there be any issues with a small block to big block swap?
Thank you in advance.
Dhasso
Just a generic question. I have a 1970 corvette with a non mtaching 350 motor. I would like to replace it with a 454 big block. Will there be any issues with a small block to big block swap?
Thank you in advance.
Dhasso
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
Purchase the 70 assembly instruction manual (AIM), turn to the optional big block section, and follow the diagrams. The AIM lists the various parts you will need and their original GM part numbers. Assembly notes also outline what changed from small block production and what parts did not.
Pro
Joined: Nov 2008
Posts: 542
Likes: 3
From: Bloomfield Hills MI
I believe there are others who have posted on making this swap. one of the bigger costs and difficulties is purchasing and locating all the various bracketry for alternator, PS pump, etc. Radiator cowl is also different. Exhaust is 2 1/2" rather than 2". Heavy duty suspension springs also needed. Not sure about radiator expansion tank, '70BB sure has one.
There will be other gotchas, hood already mentioned, plus you need LOW profile valve covers to clear, and that can rule out most of the higher performance valve train setups found in some crate motors.
There will be other gotchas, hood already mentioned, plus you need LOW profile valve covers to clear, and that can rule out most of the higher performance valve train setups found in some crate motors.
Le Mans Master
Joined: Dec 2003
Posts: 5,381
Likes: 416
From: N J
No real major issues, but whats your goal? Trying to dress the car as a correct looking big block car or just make the swap functional? On a 70 I would think you would want the car to look correct. I only ask because $$$ can be saved by not using the correct vette only parts in the process, like brackets and pulleys, etc. The same motor mounts can be used, will have to bump up the cooling system, perhaps bb springs, also the big block cars came with a rear anti sway bar. Have fun, you will love it!
Pro
Joined: Nov 2008
Posts: 680
Likes: 5
From: Denham Springs LA
Did it to my 76 and love it. 468 ci motor with 350 turbo tranny.
Spent $600 on pulleys and brackets from Zip.
Spent $900 for new dewitts radiator with elec fans.
Spent $1000 for sidepipes, headers (used) and heat shields.
Spent $400 for L88 hood.
Spent $4500 on used engine, then $2500 to fix it. For $7000 grand I could have bought a better combination engine with more hp and torque. Be careful what you buy.
Follow Easy Mikes recommendation to get an AIM and follow it for a specific Bracket and pulley setup. I copied the setup on my 71 LS5.
Good luck
Roger
Spent $600 on pulleys and brackets from Zip.
Spent $900 for new dewitts radiator with elec fans.
Spent $1000 for sidepipes, headers (used) and heat shields.
Spent $400 for L88 hood.
Spent $4500 on used engine, then $2500 to fix it. For $7000 grand I could have bought a better combination engine with more hp and torque. Be careful what you buy.
Follow Easy Mikes recommendation to get an AIM and follow it for a specific Bracket and pulley setup. I copied the setup on my 71 LS5.
Good luck
Roger
Le Mans Master
Joined: Dec 2003
Posts: 5,381
Likes: 416
From: N J
If looking correct isnt an issue, you can save some money by thinking outside the box. Here's what I did for my 77 bracket and pulley set-up. Clean, simple, open, and very inexpensive compared to correct parts. I put the money elsewhere. Good luck.
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Racer
Joined: Nov 2008
Posts: 366
Likes: 7
From: Mobile Al
You can use your org hood if you use the low profile intake manifold that comes with some of them. Yes I know it's not alum but if keeping costs down is a priority it will work till more funds are available. You can also use the tall valve covers, that are available but you won't be able to put them on or take them off (drivers side) easily if your in a big hurry. Did my swap over 30+ years ago and no big problems so far.
Drifting
Joined: Jan 2011
Posts: 1,853
Likes: 81
From: Hamilton Virginia
As others have already said, if you want it to look like the engine compartment of a big block 1970, get the aim and start buying all the parts as needed. First thing though is to see if yours was originally a big block. If so you wont have to change things like the front springs, tranny, rear axles and ujoints.
I did my swap pretty cheap, about $ 1,000-1,100 so far. My alt is on the driverside and I used pulleys and brackets from the mid 60's. I do have a high rise hood, but didnt need it if I would have kept my holly triangle shaped filter. I did change my front springs, but unless I blow out the th350 tranny or the smblock rear axles and ujoints, I have no intensions of changing them.
I did my swap pretty cheap, about $ 1,000-1,100 so far. My alt is on the driverside and I used pulleys and brackets from the mid 60's. I do have a high rise hood, but didnt need it if I would have kept my holly triangle shaped filter. I did change my front springs, but unless I blow out the th350 tranny or the smblock rear axles and ujoints, I have no intensions of changing them.
Last edited by scrappy76; Jul 10, 2013 at 10:02 AM.
Racer
Joined: Apr 2010
Posts: 352
Likes: 1
From: Central NJ
If you just want it to run, that's easy. You'll need a short shaft water pump, big block pulleys, big block accessory brackets, big block power steering hard line if you run power steering, larger exhaust, and I believe rad hoses. The radiator would be fine until you have money for a better one if you're not making big power. Overall, it's really not as hard as people make it sound. If you need help feel free to PM me.
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
When I did my 74 I didn't need a hood but I guess 70 is different???
Other than that it was acc brackets , radiator, shroud (or electric fans like I did), motor mounts and headers.
I reused my carb, distributor, PS pump, alt, hoses and the stock suspension worked just fine and my BBC was all iron
Other than that it was acc brackets , radiator, shroud (or electric fans like I did), motor mounts and headers.
I reused my carb, distributor, PS pump, alt, hoses and the stock suspension worked just fine and my BBC was all iron
Racer
Joined: Apr 2010
Posts: 352
Likes: 1
From: Central NJ
Depending on what set up you're running, that may or may not work. Typically you need the 2 groove power steering pump pulley. If you use that you can get away with the 2 groove water pump pulley (instead of the 3 groove) but you couldn't run ac.
