350 Block interchangability
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
350 Block interchangability
I'm looking at a complete rebuild of my 85 engine. Plan on going with AFR 180cc heads and comp 264 cam much like a 350 that AFR dyno tested at 420Hp. I plan on keeping the stock TPI with some minor porting. I live in Calif so I'm stuck with smog laws.
The current engine is not the original. It's a 4 bolt main bored .060 over. It has the original cast iron heads. I think I'll need a new block so I can stay at .030 over and keep compression down to 9.5:1. The question I have is how interchangable are 350 blocks? Am I limited to certain castings? With over 90 million made, there's a lot of castings to choose from. Crate motors and short blocks don't seem to exist for this year Corvette.
Any advice is greatly appreciated.
The current engine is not the original. It's a 4 bolt main bored .060 over. It has the original cast iron heads. I think I'll need a new block so I can stay at .030 over and keep compression down to 9.5:1. The question I have is how interchangable are 350 blocks? Am I limited to certain castings? With over 90 million made, there's a lot of castings to choose from. Crate motors and short blocks don't seem to exist for this year Corvette.
Any advice is greatly appreciated.
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
There is virtually no difference in a Gen 1 SBC.
I'm looking at a complete rebuild of my 85 engine. Plan on going with AFR 180cc heads and comp 264 cam much like a 350 that AFR dyno tested at 420Hp. I plan on keeping the stock TPI with some minor porting. I live in Calif so I'm stuck with smog laws.
The current engine is not the original. It's a 4 bolt main bored .060 over. It has the original cast iron heads. I think I'll need a new block so I can stay at .030 over and keep compression down to 9.5:1. The question I have is how interchangable are 350 blocks? Am I limited to certain castings? With over 90 million made, there's a lot of castings to choose from. Crate motors and short blocks don't seem to exist for this year Corvette.
Any advice is greatly appreciated.
The current engine is not the original. It's a 4 bolt main bored .060 over. It has the original cast iron heads. I think I'll need a new block so I can stay at .030 over and keep compression down to 9.5:1. The question I have is how interchangable are 350 blocks? Am I limited to certain castings? With over 90 million made, there's a lot of castings to choose from. Crate motors and short blocks don't seem to exist for this year Corvette.
Any advice is greatly appreciated.
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
There is a BIG difference between 350 SBC's.
In 1986 all became 1 pc real seal.
After 1987-1988 all were cut for hyd roller lifters but some truck and other engines thru the early 1990s still came with flat tappet cams... althou with the correct roller cam, roller lifters link bars and hold down they easily can be converted to a factory roller. Because of the roller cam these later blocks have a edge in performance over the early ones.
Since your car is a 1985 and you plan to stay with a flat tappet camshaft you need to look for an early 2pc rear seal block, which are getting harder to find these days. Oil these days has a much lower PPM of Zinc and is not formulated to be very flat tappet camshaft friendly either.
If you are able to find a later model block already set up for a roller cam, you would be money and a small amount of performance ahead IMO. All you need to buy to convert your 1985 is the correct flywheel or flex plate. The one peice rear seal blocks are much more plentiful these days.
Will
In 1986 all became 1 pc real seal.
After 1987-1988 all were cut for hyd roller lifters but some truck and other engines thru the early 1990s still came with flat tappet cams... althou with the correct roller cam, roller lifters link bars and hold down they easily can be converted to a factory roller. Because of the roller cam these later blocks have a edge in performance over the early ones.
Since your car is a 1985 and you plan to stay with a flat tappet camshaft you need to look for an early 2pc rear seal block, which are getting harder to find these days. Oil these days has a much lower PPM of Zinc and is not formulated to be very flat tappet camshaft friendly either.
If you are able to find a later model block already set up for a roller cam, you would be money and a small amount of performance ahead IMO. All you need to buy to convert your 1985 is the correct flywheel or flex plate. The one peice rear seal blocks are much more plentiful these days.
Will
Drifting
Joined: Jan 2006
Posts: 1,740
Likes: 2
From: Winchester Virginia
There is a BIG difference between 350 SBC's.
In 1986 all became 1 pc real seal.
After 1987-1988 all were cut for hyd roller lifters but some truck and other engines thru the early 1990s still came with flat tappet cams... althou with the correct roller cam, roller lifters link bars and hold down they easily can be converted to a factory roller. Because of the roller cam these later blocks have a edge in performance over the early ones.
Since your car is a 1985 and you plan to stay with a flat tappet camshaft you need to look for an early 2pc rear seal block, which are getting harder to find these days. Oil these days has a much lower PPM of Zinc and is not formulated to be very flat tappet camshaft friendly either.
If you are able to find a later model block already set up for a roller cam, you would be money and a small amount of performance ahead IMO. All you need to buy to convert your 1985 is the correct flywheel or flex plate. The one peice rear seal blocks are much more plentiful these days.
Will
In 1986 all became 1 pc real seal.
After 1987-1988 all were cut for hyd roller lifters but some truck and other engines thru the early 1990s still came with flat tappet cams... althou with the correct roller cam, roller lifters link bars and hold down they easily can be converted to a factory roller. Because of the roller cam these later blocks have a edge in performance over the early ones.
Since your car is a 1985 and you plan to stay with a flat tappet camshaft you need to look for an early 2pc rear seal block, which are getting harder to find these days. Oil these days has a much lower PPM of Zinc and is not formulated to be very flat tappet camshaft friendly either.
If you are able to find a later model block already set up for a roller cam, you would be money and a small amount of performance ahead IMO. All you need to buy to convert your 1985 is the correct flywheel or flex plate. The one peice rear seal blocks are much more plentiful these days.
Will
I know someone who has a 2pc main rear seal 350 block sitting on an Engine stand gathering dust!.........LOL
Noland
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
If you are able to find a later model block already set up for a roller cam, you would be money and a small amount of performance ahead IMO. All you need to buy to convert your 1985 is the correct flywheel or flex plate. The one peice rear seal blocks are much more plentiful these days.
Will
Will
L31 350 Vortec block from '96 -00 truck.1 pce seal , roller cam.
Plenty around ,50% chance it will be 4 bolt mains also ; not necessary but nice to have
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