[1hotboat]

Is there a difference between 781 and 049 oval port BBC heads? If so what is it.

Thanksdevil

 

[motormonkey]

Yes thier is. 049 are a good head for a semi stock motor with some bigger valves. The 781 have more performance potential with even bigger valves. Its a can of worms and the 049 with a 2.19 intake are a good setup.

 

[1hotboat]

Yes thier is. 049 are a good head for a semi stock motor with some bigger valves. The 781 have more performance potential with even bigger valves. Its a can of worms and the 049 with a 2.19 intake are a good setup.

/\

It's a can of worms? Sorry hard to read, what's a can of worms? Please explain.....as I get it 781s are better? I would like to know witch ones are the best to start with for a lake boat (jet) that will run good on pump gas, at 10.5 compression.

Thanks

 

[1hotboat]

Just looking for a little heredevil

 

[Cas]

hopefully this will help you. The 781 heads have 256/114 cc port size runners, with 118cc combustion chambers.
The 049 heads have 255/119 cc port size runners, with 122cc combustion chambers.
It's really a toss up on which ones to use as the 049's flow more but the 781's will give a little more compression. Personally, I went with the 781's and had 2.19 intake valves and 1.88 exhausts put in. The same can be done to the 049's without any issues.

 

[1hotboat]

hopefully this will help you. The 781 heads have 256/114 cc port size runners, with 118cc combustion chambers.
The 049 heads have 255/119 cc port size runners, with 122cc combustion chambers.
It's really a toss up on which ones to use as the 049's flow more but the 781's will give a little more compression. Personally, I went with the 781's and had 2.19 intake valves and 1.88 exhausts put in. The same can be done to the 049's without any issues.

Thanks Cas but please next time print for this Old mans eyes.Had to get out the mag. glass

 

[Cas]

I edited it....is it better now? I know it is for me

 

[1hotboat]

/

Yepp that helps. Thanks..Sucks getting old)eek)

 

[jetboatperformance]

Heres a great website and valuable resource for anyone chasing casting # info Tom
http://www.mortec.com/castnum.htm

 

[Cas]

I know what you mean. When I turned 46 it seemed 1 day I could see just fine and the next I needed glasses. Now that I'm 52, I've had 7 new pairs of glasses that are getting stronger and stronger. sphss

 

[jetboatperformance]

I know what you mean. When I turned 46 it seemed 1 day I could see just fine and the next I needed glasses. Now that I'm 52, I've had 7 new pairs of glasses that are getting stronger and stronger. sphss

Costco has those specs in the handy economy packs !

 

[1hotboat]

Heres a great website and valuable resource for anyone chasing casting # info Tom
http://www.mortec.com/castnum.htm

Tom great imfo but what do you think are the best heads to start with? I have 781s But don't want to waste money,trying to do the best the first time.

Thanks

 

[Malcolm]

I think you'd need some pretty good eyes to see the difference in them. I have a set of 781s and I plan on using them when I get around to building my Chevy motor. If you want big power you'll trade up for some rectangle ports anyway.

 

[motormonkey]

To simplify. 781 have the largest cast chamber. What that means is less valve shrouding. Compression doesnt come into play since you can deck to get it. Can of worms, because you can hog out 049 but you may find water.
781 will take a larger valve safer.
What are you building, how much do you want to/will spend and what are you expecting to do with it?

 

[1hotboat]

Thanks alldevil

 

[PDX Jet]

Now explain the 292's which have the same runners and a 110cc chamber. Whats better?

 

[Cowboy_Mike]

hopefully this will help you. The 781 heads have 256/114 cc port size runners, with 118cc combustion chambers.
The 049 heads have 255/119 cc port size runners, with 122cc combustion chambers.
It's really a toss up on which ones to use as the 049's flow more but the 781's will give a little more compression. Personally, I went with the 781's and had 2.19 intake valves and 1.88 exhausts put in. The same can be done to the 049's without any issues.

Hi, I am newby here. I don't the cc's you mentioned above. My book said they are 110, and the set I have cc out to 111. I don't think they have been surfaced. The 76 454 I pulled them off of was bone stock out of a Suburban. If they are 118 stock, I need to know. I am thinking of building my 454, and I will need to get different heads.