049, 781, 188??
 

Which of these heads came on the 454 Mag? I was thought it was the 188. And that is the same head that came on the L88 454. Is this right? Or who can straighten me out on this.
What did the 049 and the 781 come on?

Re: 049, 781, 188??
 

I dont think the 781 or 049 ever came on a merc engine, at least not since they stopped making them in the early 80's. Actually, the oldest castings I have seen were 1979. Im not sure exactly when they stopped making them. The rectangular heads 188 came on the merc mag engines except a few in 87 that got attached to an alpha had peanut ports. This is all stuff Ive read and not sure if its all accurate.

Re: 049, 781, 188??
 

049 & 781 were GM big ovalports without hardened seat back when leaded gas was around. DO not use them now or you will have big problems unless you put seats in them. If doing that just buy the Dart Iron Eagle and be done.

Re: 049, 781, 188??
 

Very true, they need exhaust seats for sure and bigger valves and guides and spring pockets cut and guides cut for seals and ported and it all adds up. I probably have 1500 in each set of 049's and 781's I have. If Edelbrock had their marine aluminum ovals when I did this, Id have bought them instead.

But, if you can find these already done reasonable cheap, they work well.

Re: 049, 781, 188??
 

Whatcha up to know? I think your boat has the .188 castings.

Re: 049, 781, 188??
 

188's should be on them.

Re: 049, 781, 188??
 

They do work, I did the same about 8 years ago and had more into them than a new set, but they worked.

Re: 049, 781, 188??
 

Yep, I know that's what's on there. :drink: And I'm not up to nutin. :drink:
I was really just kind of confused with all the casting numbers out there. Isn't there a 9xx something casting that guys talk about. Is that a later 454 mag head?

What engines did GM put these on?

Thanks for the info guys.

Re: 049, 781, 188??
 

The 049's came on many of the Merc 330hp engines from the 70's to the early 80's. And I agree with Linster, they NEED hardened seats if you are going to run stainless valves in them. We found this out back in the mid 1980's as the stainless valves were pounding the seats and sinking into the heads, but once done correctly they ran very well! And I also agree with Linster that it takes a LOT of money to modify the 049's to make them a good head...i.e. larger valves, hardened seats, bowl porting, etc. The Merlin oval port head comes pretty much ready to go. The only thing is they need a little clean up work in the port bowls.

Re: 049, 781, 188??
 

990 casting