What Heads Are On This 5.7L GM?

[Quarterwave]

Hi everyone,

I just picked up a 5.7L small block Chevy engine to replace the ceased 5.0 Mercruiser that I have in my bowrider.

While I need to prepare the motor for marine use, can anyone tell by the intake manifold what heads are on this engine?

It is a 1986 casting (10054727) and came out of a show car that was being built (previous owner was putting in an LS) but it seems like it has a 12 bolt manifold, which would tell me that it has Vortec heads.... but I'd appreciate having more informed opinions confirm or deny it...

 

[Scott Danforth]

Hi everyone,

I just picked up a 5.7L small block Chevy engine to replace the ceased 5.0 Mercruiser that I have in my bowrider.

While I need to prepare the motor for marine use, can anyone tell by the intake manifold what heads are on this engine?

It is a 1986 casting (10054727) and came out of a show car that was being built (previous owner was putting in an LS) but it seems like it has a 12 bolt manifold, which would tell me that it has Vortec heads.... but I'd appreciate having more informed opinions confirm or deny it...

Wrong.

12 bolts in the intake is NOT a vortec. Vortec heads have 8 bolts holding the intake and they are straight up and down.

without casting numbers on the head, its a crap shoot at what you have. hope you have the3901068 heads with the 64cc chamber and not the 76 cc smog motor heads

pull the valve cover and either look up your casting numbers on Mortec or post them here.

your block 10054727 is a 1-piece RMS block for 1986-up and was cast in Canada indicating it was a truck motor (St Catherine engine plant only produces truck motors)

 

[FreeBeeTony]

If the intake has 12 bolts.......they're not Vortec.

 

[Bondo]

Ayuh,... Hard to see in the picture, but the center 4 bolts look vertical to the block, which makes it a period correct 1986 to '96 motor,....

Pre-'86, all 12 bolts are 90? to the heads themselves,....

Post-'96, of course is Vortec, with only 8 intake bolts,....

 

[Quarterwave]

Thanks everyone, much appreciated!