Old engine block versus newer engine block???
Thread Starter
Intermediate
Joined: Nov 2004
Posts: 28
Likes: 0
Old engine block versus newer engine block???
I am upgrading the sad L48 in my 75 Stingray and am considering a crate engine versus rebuilding and modifying my current engine. With the many engine improvements since 1975, is there any REAL difference in engine blocks if I keep it carburated? Or are more current engine blocks better? What would you experts do out there
Pro
Joined: Sep 2002
Posts: 690
Likes: 1
From: near Memphis TN
Can't beat those hydrolic rollers. Some good crate engines out there.
On the other hand, the benifit to using your old engine is you have a seasoned block that may be more reliable if rebuilt right, probably rebuilt cheaper and to your specific specs if you find the right engine builder.
On the other hand, the benifit to using your old engine is you have a seasoned block that may be more reliable if rebuilt right, probably rebuilt cheaper and to your specific specs if you find the right engine builder.
Le Mans Master
Joined: Apr 2001
Posts: 5,941
Likes: 281
From: Was New Orleans but swam to Baton Rouge LA
Cruise-In IX Veteran
The older blocks have a better metal content in them and are often stronger requiring less machining between rebuilds. A new block like stated has the Roller cam which is a big improvement in idle quality. They also have the 1 piece rear seal which is a better seal that does not leak as easily as a 2 piece does. I personally went with a ZZ4 Crate engine when I had to rebuild mine. The price on the crate was hard to beat when I looked at adding those parts to my exisiting 350.
Abby Normal
Joined: Dec 2001
Posts: 53,206
Likes: 92
From: Press "2" for English
everything is relative but if it were me (and it was several months ago), i'd go with a later block. the primary reason i say that is soley for the roller lifter advantage, with the one piece rear main being a far second. other than those two differences, everything else pretty much is interchangeable.
another advantage i don't know if you'll use is if you get a complete late model block, the later rods are supposed to be better than any of the early rods short of the "pink" rods.
while some say the older blocks are better iron than the newer blocks, i'd disagree with that in the case of the late 70's/early 80's blocks. the heads of that era were cast to reduce weight and some of the blocks were too. the older blocks, the engineers just said, "i think we can take some out here", whereas in the newer blocks, they've been engineered with minimum weight and maximum strength in mind.
just my $.02.
another advantage i don't know if you'll use is if you get a complete late model block, the later rods are supposed to be better than any of the early rods short of the "pink" rods.
while some say the older blocks are better iron than the newer blocks, i'd disagree with that in the case of the late 70's/early 80's blocks. the heads of that era were cast to reduce weight and some of the blocks were too. the older blocks, the engineers just said, "i think we can take some out here", whereas in the newer blocks, they've been engineered with minimum weight and maximum strength in mind.
just my $.02.
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
I agree with most of the above. There are "good iron" blocks out there in late model. I have an 88 350 from a 1-ton cube van and it is supposed to have a higher nickel content than the 1/2 ton and passenger blocks. It seems physically heavier than the 93 350 from a 1/2 ton moving them around. The 1-pc rear seal is a great thing, my 95 Suburban has over 200k miles now and no rear main leaks. All small-block heads can interchange (except LT1) so you can use whatever heads and intake you like and carburate it or fuel inject it. Unless you need numbers matching, I don't see much reason to choose early over late blocks.
Drifting
Joined: Feb 2005
Posts: 1,738
Likes: 2
From: San diego ca
I used a '87 block for the roller cam...I went ahead and adapted the 1pc rear seal to a 2pc...set up properly a 2pc real seal works just fine.
The move to the 1pc rear main seal was accompanied with the change to a smaller flywheel/crankshaft bolt circle, 3.00" vs. the earlier 3.58" dia. pattern that was used with 2pc rear main seal engines. Large and small pattern flywheels/flexplates are not interchangeable. So if you go to the 1 pc seal crank - dont forget a new flywheel/flexplate
The move to the 1pc rear main seal was accompanied with the change to a smaller flywheel/crankshaft bolt circle, 3.00" vs. the earlier 3.58" dia. pattern that was used with 2pc rear main seal engines. Large and small pattern flywheels/flexplates are not interchangeable. So if you go to the 1 pc seal crank - dont forget a new flywheel/flexplate
Last edited by fauxrs2; Mar 20, 2007 at 07:48 PM.
Racer
Joined: Nov 2006
Posts: 435
Likes: 7
From: Wake Forest NC
I'm at the same point nvvetgirl, after all the comparisons of rebuilding the old or going w/crate (3900 to rebuild vs 3950 for ZZ4), the ZZ4 is a no brainer to me. Oh, and the 3900 to rebuild mine doesn't include a forged crank and better rods, but does include AFRs. The crates are a hard act to follow.
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Instructor
Joined: Dec 2002
Posts: 222
Likes: 0
From: Leander TX
An example of waking up an L-48 with few well picked top end components (if the bottom end is ok). Check out this current thread.
http://forums.corvetteforum.com/show....php?t=1653661
If you want to throw money at it.. go big block .. ask me how I know
-F
http://forums.corvetteforum.com/show....php?t=1653661
If you want to throw money at it.. go big block .. ask me how I know
-F