I am looking to buy a Buick 350 block but I need to be pointed in the right direction. I am looking to go though the engine and rebuild it. I have a stock 72 Skylark 350 right now and I am keeping it a stock looking car (engine is number matching to the car so I don't want to rebuild that engine because of the value it adds to the car). So am looking for a block but I don't know what year to buy. I want to build up the block to be a street car but with some performance in it. Something that can get up and go here and there. I just want to be pointed in the right direction. Thanks guys.
Rebuilding a 350
- Thread starter J-Man
- Start date
Hello J-man,
i have a 1972 Buick 350 engine in my garage. I was originally going to rebuild it. I ended up swapping out engines instead. If your near WI, I will sell it to you for cheap. I have the 4 bbl intake, heads, and the core engine. I can throw in a 4 bbl Holley carb also.
Let me know if your interested,
John
i have a 1972 Buick 350 engine in my garage. I was originally going to rebuild it. I ended up swapping out engines instead. If your near WI, I will sell it to you for cheap. I have the 4 bbl intake, heads, and the core engine. I can throw in a 4 bbl Holley carb also.
Let me know if your interested,
John
John
I am interested in that seeing I have a 72 Skylark. Could you email me at manogj44@uwosh.edu for more information about the block and send pictures? I do live in Wisconsin.
Jake
I am interested in that seeing I have a 72 Skylark. Could you email me at manogj44@uwosh.edu for more information about the block and send pictures? I do live in Wisconsin.
Jake
If you can, try to track down a book called ""Building the Buick Performance Engine" by Steven Dove.
That will tell you all about rebuilding the Buick 350 (and 455), and your machinist should also follow the instructions it gives.
Of course we're here to help with any more specific questions...
-Bob C.
That will tell you all about rebuilding the Buick 350 (and 455), and your machinist should also follow the instructions it gives.
Of course we're here to help with any more specific questions...
-Bob C.
For the 350 motors, I'm not aware of any year which is better than another. However If the motor has previously been rebuilt, make sure the cylinders won't need to be bored to the point where the walls are too thin (especially if the motor has been bored +0.030 previously).
-Bob C.
-Bob C.
74 and newer is supposed to use the stronger cap screw rod.
1968-70 have the shallow dish pistons. all years of the 350 are supposed to have pretty much the same combustion chamber in the head so the only way to up compression is with piston dish or milling the block / head / intake.
the older castings MAY also flow slightly better.
there's not supposed to be much difference between the actual blocks.
1968-70 have the shallow dish pistons. all years of the 350 are supposed to have pretty much the same combustion chamber in the head so the only way to up compression is with piston dish or milling the block / head / intake.
the older castings MAY also flow slightly better.
there's not supposed to be much difference between the actual blocks.
Is the only way to tell if a block has been bored with a micrometer or is there stamp from the machinist on the block (sounds kinda like a dumb question)? So any block really is fine for my application because I will be going through the engine, but if I want to up the compression for performance I will need dish piston, intake and older head with a valve job on them?
Is the older blocks more or less desired for the oiling? It seems to me that all years of engines have their strengths and weaknesses but I don't know which is the best/stay away from.
Jake
Is the older blocks more or less desired for the oiling? It seems to me that all years of engines have their strengths and weaknesses but I don't know which is the best/stay away from.
Jake
any advantage in oiling would be with the newer blocks. and that mostly applies to the 455s. check to make sure your oil pickup is 5/8" diameter, otherwise you'll want to get a large pickup from a v6.
but if I want to up the compression for performance I will need dish piston, intake and older head with a valve job on them?
why older heads? the heads are all pretty much the same from 68-81. the only certain benefit to the old engines is the hi-comp pistons and that assumes that you can re-use the pistons AND that it's not a low comp two barrel build from the factory.
Is the older blocks more or less desired for the oiling?
1968-70 oil the rockers by weeping through the rocker shaft. many people convert to through the push rod oiling and close off the passage between the block and heads but either system works fine.
but if I want to up the compression for performance I will need dish piston, intake and older head with a valve job on them?
why older heads? the heads are all pretty much the same from 68-81. the only certain benefit to the old engines is the hi-comp pistons and that assumes that you can re-use the pistons AND that it's not a low comp two barrel build from the factory.
Is the older blocks more or less desired for the oiling?
1968-70 oil the rockers by weeping through the rocker shaft. many people convert to through the push rod oiling and close off the passage between the block and heads but either system works fine.
BCCBuickV8
Member
This is a useful read
sean buick 76
Active Member
I know I am late to the party but here is some info:
The 68 and 69 Buick 350s oil the top end of the engine though a passage into the heads... This seems to work fine
The 70-81 engines oil the top end of the engine through the pushrods which also works well. However you just need to know this in the case of mixing and matching parts from different engines. The pushrods are a different diameter and obviously hollow for the later versions
The 74-81 heads have different shaped passages, and we prefer the 68-73 heads for performance use. Some of the 75-81 heads have oversized valves in the exhaust side, bt no real performance gain in stock form.
The 68-71 heads are more likely to crack, MANY cracked early heads out there...
In mid 72 Buick added an extra passage to the heads and this eliminated the cracking issues. The blocks also received an extra "scallop" which covers the new head passage for a dead end but it is needed to keep the coolant from pouring into the valley area of the engine.... If you use late heads on an early block the coolant will pour into the block and make a mess.
The later blocks can be used with any year head even early versions.
If converting the 68-69 engines to pushrod oiling just block the oil passage in the block and use all the newer style parts for the top end...
One bit of testing that i am working on is flow testing the 68, 69, 70, 71, 72, 73, 74 and 77 heads so that I can see which years flow the best....
So far the most desirable head seems to be the 73 versions because they have the extra coolant passage but they are not the poorer flowing style from 74 and later...
So if you are buying a complete engine to do a quick rebuild I think the 68-70 engines are the best...
If doing a modified rebuild then the best is to use a 74-81 engine with 73 heads... this way you get the stronger rods, pushrod oiling system, larger pickup in the oil pan (I don't remember which year that started).
Another warning though is if mixing and matching the rods and pistons there are two different weights... The 68-72 engines have the lighter rods and the crank is balanced to match that. If you swap to the stronger 74-81 rods it throws off the balance of the engine... Plus most engines under 500 HP are fine with the "weaker" old style rods.... Its only for the 500+ HP Buick 350s that we really need the later rods anyways...
Regarding pistons there are several dish and compression heights on the 350 pistons over the years... Ranging from about 10:1 compression down to about 7.8:1. The advertised compression ratios were all HIGHER than the actual compression ratio they had....
Scotty Brown (Buyracingparts) is making nice light forged pistons for us for about $600 which can be custom ordered to get any compression ratio you want without milling much off the block.
All the Buick 350 heads are about 58 CC unless they are milled.
I checked the compression ratio on the 71 Buick 350 in my Skylark and it was about 7.9:1 compression, with a Poston 114 cam, home head porting, custom intake manifold and some boost it still made 450 HP at the tires but it really needed that boost!
The 68 and 69 Buick 350s oil the top end of the engine though a passage into the heads... This seems to work fine
The 70-81 engines oil the top end of the engine through the pushrods which also works well. However you just need to know this in the case of mixing and matching parts from different engines. The pushrods are a different diameter and obviously hollow for the later versions
The 74-81 heads have different shaped passages, and we prefer the 68-73 heads for performance use. Some of the 75-81 heads have oversized valves in the exhaust side, bt no real performance gain in stock form.
The 68-71 heads are more likely to crack, MANY cracked early heads out there...
In mid 72 Buick added an extra passage to the heads and this eliminated the cracking issues. The blocks also received an extra "scallop" which covers the new head passage for a dead end but it is needed to keep the coolant from pouring into the valley area of the engine.... If you use late heads on an early block the coolant will pour into the block and make a mess.
The later blocks can be used with any year head even early versions.
If converting the 68-69 engines to pushrod oiling just block the oil passage in the block and use all the newer style parts for the top end...
One bit of testing that i am working on is flow testing the 68, 69, 70, 71, 72, 73, 74 and 77 heads so that I can see which years flow the best....
So far the most desirable head seems to be the 73 versions because they have the extra coolant passage but they are not the poorer flowing style from 74 and later...
So if you are buying a complete engine to do a quick rebuild I think the 68-70 engines are the best...
If doing a modified rebuild then the best is to use a 74-81 engine with 73 heads... this way you get the stronger rods, pushrod oiling system, larger pickup in the oil pan (I don't remember which year that started).
Another warning though is if mixing and matching the rods and pistons there are two different weights... The 68-72 engines have the lighter rods and the crank is balanced to match that. If you swap to the stronger 74-81 rods it throws off the balance of the engine... Plus most engines under 500 HP are fine with the "weaker" old style rods.... Its only for the 500+ HP Buick 350s that we really need the later rods anyways...
Regarding pistons there are several dish and compression heights on the 350 pistons over the years... Ranging from about 10:1 compression down to about 7.8:1. The advertised compression ratios were all HIGHER than the actual compression ratio they had....
Scotty Brown (Buyracingparts) is making nice light forged pistons for us for about $600 which can be custom ordered to get any compression ratio you want without milling much off the block.
All the Buick 350 heads are about 58 CC unless they are milled.
I checked the compression ratio on the 71 Buick 350 in my Skylark and it was about 7.9:1 compression, with a Poston 114 cam, home head porting, custom intake manifold and some boost it still made 450 HP at the tires but it really needed that boost!
The advertised compression ratios were all HIGHER than the actual compression ratio they had
that applies to pretty much any factory engine at least until you have a machinist blue print it.
as a fer instance, actual deck height of the block is usually a bit taller than theoretical design spec. that's going to drop compression over "factory rating" all by itself.
Regarding pistons there are several dish and compression heights on the 350 pistons over the years...
OEM rods are all the same length though?
if the later rods happen to be slightly longer we could pin early shallow dish pistons on them and get a bit more compression.
obviously, the rotating assembly should *always* get rebalanced after changing major components.
that applies to pretty much any factory engine at least until you have a machinist blue print it.
as a fer instance, actual deck height of the block is usually a bit taller than theoretical design spec. that's going to drop compression over "factory rating" all by itself.
Regarding pistons there are several dish and compression heights on the 350 pistons over the years...
OEM rods are all the same length though?
if the later rods happen to be slightly longer we could pin early shallow dish pistons on them and get a bit more compression.
obviously, the rotating assembly should *always* get rebalanced after changing major components.