BEST 59AB big bore head gasket on 8BA block
 

JWL or Old Ron or somebody. A friend called me this morning, he is building a 50 Merc 1/8 bore, wants to know if he can use 59 big bore BEST gaskets on the 8BA block. He has got the holes in front of the block and pumps blocked. He said the gasket has a no. 536 1 on it. Thanks Walt

Re: BEST 59AB big bore head gasket on 8BA block
 

Assuming he´s going to use 59AB heads since he blocked of for using early style pumps...and then the 59AB gasket is the one that will match the heads.

Re: BEST 59AB big bore head gasket on 8BA block
 

Somebody did this on the engine in my truck in the avatar. WHY? Didn't know it till the gasket failed and I had to replace the head gaskets. Used Best big bore gaskets. Engine is 3.312X4. Been running fine for over three years. I did use 8BA style gaskets.

Re: BEST 59AB big bore head gasket on 8BA block
 

I use the gasket which matches the block.

Re: BEST 59AB big bore head gasket on 8BA block
 

Anybody know why someone would use 59A gaskets on an 8BA block with 8BA style heads? Makes no sense to me.

Re: BEST 59AB big bore head gasket on 8BA block
 

I know people do it but I think they just want it look like an early engine. Walt

Re: BEST 59AB big bore head gasket on 8BA block
 

Have no clue why you would use a 59AB gasket on a 8BA head and block.
Why you use the 59AB gasket with the heads is that they are designed for best flow with center outlet and often combined with early style pumps you have a 59ab cooling system.

Re: BEST 59AB big bore head gasket on 8BA block
 

I always use the gasket that matches the head. Guess it doesn't make any difference. I think the 8BA gasket channels the water in a different direction. But, these flatheads are funny critters and usually do as they please, just like my dog.

Re: BEST 59AB big bore head gasket on 8BA block
 

The water flow improvements made to the block design of the 8BA are impeded by the use of unaltered 59A gaskets and heads. In most cases it seems to work ok but there would be more cushion if the coolant flow more closely matched the designed configuration.

Re: BEST 59AB big bore head gasket on 8BA block
 

Gasket has to match the head. ab heads on late 8ab block. Also two holes need to be blocked.

Re: BEST 59AB big bore head gasket on 8BA block
 

Why did somebody do that? Probably had the new 59 series gaskets on hand and didn't want to buy new 8ba ones if they could make the early ones work.

Re: BEST 59AB big bore head gasket on 8BA block
 

NO, the gasket does NOT have to match the head. The 8BA (and 1BA) block castings improved coolant flow to the rear cylinders. As much as reasonable that design should be utilized.

Re: BEST 59AB big bore head gasket on 8BA block
 

My thinking is that the headgasket dictates the flow through the head and using a gasket designed for front outlet 8BA will give you an uneaven cooling of the head with center outlet.

Most people using 59AB heads on an 8BA also uses the early pumps and loose the bypass of the newer style pumps and some of the improved flow.

So basicly having a 59Ab cooling system with the exception of the differences in core style of the block my vote goes to using the gasket that match the heads.

Re: BEST 59AB big bore head gasket on 8BA block
 

The cooling of the cylinders to a more equal degree is what the design changes were about. The 8BA gasket is the better choice.

Re: BEST 59AB big bore head gasket on 8BA block
 

I´ll get the design change to compensate for the front outlet but if it was a big improvement using 59AB style parts why not open up the rear of the block on earlier ones and use the new style gaskets there to then ?

Using older style pumps on newer block what is the flow compared to newer pumps ?

Would be interesting if anyone have done some real testing with tempsensors installed on individual cylinders.

Interesting subject the cooling of the flathead...always something new to think of.