3.8 Blocks

cml87type

New Member
Hey guys...have a chance to pick up a regular regal for a parts car cheap. Good for bolts, sheet metal patches, etc. Was wondering if the non-turbo 3.8 and the turbo 3.8 block is the same? I know somebody on here knows the answer. Thanks for the help.

Clayton
 
Depends on what year we are discussing. Also depends on the car also still has its correct block, early 85 and older have a 14 bolt oil pan which also makes the front cover diffrent and it doesnt have the boss for the oil return. Some later 85 blocks have 20 bolt oil pan and 86-87 front cover but has 140 casting number which also does not have oil return boss. 86-87 blocks have a casting number that ends with 109 and the 89 turbo ta's also have a 109 block but theirs also have sg1 cast into the side. Now if your 87 gn blew a engine back in the day your new gm engine could also have the correct 109 on the block but also have sg1 which is incorrect. I also imagine if you blew your na 1984 engine in 1989 you probably would end up with a NA 109 engine which is incorrect but would do the job. Also if somebody swapped in a junkyard motor of a unknown year it would work but may not necessarily be correct so you need to look on the driver side on the block in the back for the casting number to verify that it is what you need . You will need to jack the car upband look at it from underneath the car . Bring a flashlight and a rag
 
It is very easy to identify a 109 block, it will have water drain plugs on each side just below the head surface.

If the plug is a stock one, it will have a square head. :)
 
86-87 and 4th quarter 85 have 109s
A in the vin are 3.8s with 2BBl 4 BBl are 4.1s
you can see the boss on the front an upside down U flat surface to drill the return line on Pass front of block.
 
If it's an 84-87 and the body is rust free and the header panel is good that would make it worth getting. Who cares if it's a 109 or not as long as the block is good. Plenty of guys running 4.1s and you don't hear them crying about not having a 109;)
 
Iirc, Isnt the 109 block around 10 lbs heavier than the previous blocks. And rods were better , i dont know what was done to them, and for sure the crank has rolled fillets.
 
I also have a question. Do the 84/85 Turbo blocks have anything specific to them? Or could I just take any old 84/85 3.8 block either NA or Turbo, and use it for said turbo application?
 
I also have a question. Do the 84/85 Turbo blocks have anything specific to them? Or could I just take any old 84/85 3.8 block either NA or Turbo, and use it for said turbo application?

Any 84/85 block will work just fine. The block casting has no bearing what so ever on performance or durability. Make sure you have a turbo crank, rods and pistons. Some will be 14 bolt and some 20 bolt pans though. Brad
 
So the earlier block has same weight? I know the 8445 casting later head is the "heavy" head but dont know its years of run.
 
Iirc, Isnt the 109 block around 10 lbs heavier than the previous blocks. And rods were better , i dont know what was done to them, and for sure the crank has rolled fillets.

Turbo 109's and 4.1's had the rolled fillet crank. It could show up elsewhere but I think it would be a fluke. (like a dealer crank replacement or something)

As for the 8445 head I'm pretty sure the only difference between the 8445 and the 6293 you're really going to notice (and I know there are other slight differences but I don't think it's worth mentioning) is the egr is a little different and I believe the heads are tapped for metric (8445) instead of SAE (6293)
 
Interesting that the 4.1 has rolled fillet crank, did not know that. Im fairly sure the 8445 head is heavier , and gm just decided to use it acrosse the board on all motors instead of making na and turbo app.
I wonder, does the 4.1 crank have the offset crank pins to obtain the even fire? Those off sets scare me to death when i look at the 109 crank, seems it would break there!
 
Interesting that the 4.1 has rolled fillet crank, did not know that. Im fairly sure the 8445 head is heavier , and gm just decided to use it acrosse the board on all motors instead of making na and turbo app.
I wonder, does the 4.1 crank have the offset crank pins to obtain the even fire? Those off sets scare me to death when i look at the 109 crank, seems it would break there!

strength wise. there is almost no difference between early and late blocks.

the extra weight comes from the closed valley and slightly longer pan rail.

4.1 crank is the same as turbo crank. has offset pins.

difference in the 8445 heads to the 6293 is the small bridge present at the end of the water ports. this has not been proven to make the 8445 any better.

A.j.
 
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