Block casting number

[MSKBuick]

I was thinking of purchasing a used 3.8L turbo block, and the casting number is 25524140, and above it is 3.8L GM, any idea what this is since I thought turbo blocks were 109's?

[MSKBuick]

Searching the website I see this is a 3.8L RWD block, could this have been in a turbo buick from the factory, how can I check?

[Keller]

Our info indicates that is not a turbo block. However, chances are that there is little, if any, difference between a turbo and non-turbo block other than the crank, pistons, rods, etc. for '85. So long as you are rebuilding it, it may not matter. But the chart clearly states that it is not a turbo block.

[pfredricks]

MSK,

What are your indications that this is a turbo block?

I, too, have a 4140 block that was sold to me from an 85 GN. Having taken this motor apart, I can see that it has the turbo crank, turbo pistons and 763 rods and all the other nasty goo that comes with a motor that has 100K on it.

But like Scott says the chart shows it is a RWD NA block.

One thing is sure: anything other than a Stage or 109 block is not as stout and limits you HP potential. The price should be adjusted accordingly.

[MSKBuick]

Paul, he said it has the 763 (2 dot) connecting rods, rolled filet crank and the 445 heads, he said it is out of an 85 turbo.

[pfredricks]

MSK,

Seems like you are looking at the same situation I was in when I bought mine. My goals for this motor are modest, it's more for my education than to beat the guy down the street. I do not have the HP sickness to the degree others have, but I think I'm moving in that direction.

I don't have a definitive answer to your original question of "what the heck is it?" but IMHO I think Buick used the 4140 blocks in turbo applications. The rolled fillet cranks were used on NA motors, so were the 8445 heads. I'm not sure about the rods, but the pistons were special for turbos motors.

I would say that you can get this block on the cheap. As long as your sickness is not too bad you should be fine. Should you be taken ill, consider buying the steel main caps, girdle and decent fasteners. Have the crank balanced, set your tolerances to spec and don't push too hard.

Thanks for the input.

[Keller]

Perhaps we should put a note with an asterisk on the list that these might be found in TRs as well.

[NOTACARLO]

4140 I believe is the head casting. (Scott/Ken feel free to correct me)

[kenmosher]

Nope, block ... it seems the 4140 was kind of a late '85 block in the TRs.