Ported Chevy 781 heads

[Carnut1]

0219161525.jpg

I call this one the good port or the hook port. I like the way it dumps toward the center of the cylinder. I originally got these heads on trade when I built a 496 for a monster truck 15 or so years ago. They had 2.06/1.77 valves 468 cubes 12.5 pistons on 3/8 rods ran low 10's and they spun it so fast each rod elongated enough to leave deep notches in the pistons from the edge of the chamber. One rod was cracked from elongation. These heads have at least 100 hours of metal removal on them. I have only done a few sets of 781's but I like them. These have 2.3/1.88 valves and very high bowl ratios very thin valve job. Done about 5 years ago.

[Carnut1]

0219161524.jpg

I call this the bad port or the straight port. I do not like how it dumps toward the cylinder wall like a Ford or Ls1.

[Carnut1]

0219161526.jpg

781 chamber 2.3/1.88

[Carnut1]

0219161604.jpg

Port texture 60 grit rolls.

[Carnut1]

0219161755.jpg

Not a big block expert but the ones I have built the owners truly loved them and still have them many years later. Flowsheet. Multiple problems included drilling bore fixture and tapping for bolts and valves hitting the 4.3" bore hole. I did need to offset the head enough to open the valves that will change the flows. Not sure I want to notch the bore fixture. I was surprised the bad port has as much swirl as it does.

[vortecpro]

Finally, something I can sink my teeth into .

[F-BIRD'88]

Good job. Yup those heads work real good when they are done right.

[cv67]

like watching homejob builds keep the pics coming

[Carnut1]

Finally, something I can sink my teeth into .

Wish I still had a set of peanut heads done up!

[Carnut1]

0219161856_HDR.jpg

hook roof

[Carnut1]

0219161854_HDR.jpg

Straight roof

[Bob Hollinshead]

Nice results!

[Carnut1]

Nice results!

Thanks, I am not sure what a decent oval port flows. Just had an itch to pop these on the bench. I have these ports measured and poured in a notebook. I will look up more specs tomorrow.

[rally]

i had a set of 049 oval port heads, similar to the 781. 049 had better exhaust port vs the 781. Anyhow my 049 had a decent bowl job with 2.19 intake, 1.88 exhaust valves installed with good springs. 3 angle cut on the seats. turned in the 10s with a 427 ci Motor. These 781-049 are good heads and flow well up to 6500 RPMs.

[In-Tech]

I was surprised the bad port has as much swirl as it does.

The "bad" port isn't as bad as many think, it can flow into the center because of the swirl.