454 BBC 781 heads

[Dave]

I saw a pair of 781 heads f/s in stock form. I've heard these heads have good air flow characteristics and compression comes in around 8.5-9.0
What has anyone heard about them good, bad, indifferent. LMK

[SCOTI]

One of the best 'bang for the buck' bbc heads offered.

Mild port work & a good valve job & they'll flow as much as high dollar aftermarket heads. I don't recall typical compression ratios but I believe the 781's on my RetroRod combined w/a forged flat-top yielded 9.5:1. It will mainly depend on deck height, if the heads have been milled/surfaced, & what pistons are used.

[Dave]

Thanks SCOTI.

[BigBlocksRule]

You ain't gonna be anywhere near 9.5:1 with flat tops and open chamber heads, period.
With 119cc chambers and 3cc valve reliefs with a decked block and .040 quench, you'll be at 8:1. It'll take a small dome to get you up to 9 or 9.5:1.
With a good bit of port work, large valves, etc., you'll be as good as entry level aluminum heads, I've seen well done ones flow in the 340cfm range. They won't hold a candle to a good race head which are all well over 400cfm, but will be great for daily driver or mild racing.
Don't get too tied up in big port work...stock valves with a good bowl blending and a bit of short turn work, good 3-angle valve job and some necked-down valves plus some small dome pistons will get you a very good head, capable of 600hp or so on a 454.
Or forget the domes, go with a forged and studded bottom end and add forced induction, that's a perfect compression ratio for a hairdryer or huffer!

[Moostifer]

what they said...

I'm running 781's... larger valves, bowl blend, 3 angle, ports matched to intake runners, etc..

good heads stock...

great heads if they are given to the right machine shop...

but, as cheap as uluminum heads are now, for a few hundred more...

[77BBGMC]

Originally Posted by Moostifer

what they said...

I'm running 781's... larger valves, bowl blend, 3 angle, ports matched to intake runners, etc..

good heads stock...

great heads if they are given to the right machine shop...

but, as cheap as uluminum heads are now, for a few hundred more...

Ditto...781's seem to perform well.

[SCOTI]

Originally Posted by Moostifer

what they said...

I'm running 781's... larger valves, bowl blend, 3 angle, ports matched to intake runners, etc..

good heads stock...

great heads if they are given to the right machine shop...

but, as cheap as uluminum heads are now, for a few hundred more...

Post up links to aluminum heads that are "a few hundred more".

[Desert1957]

http://www.profilerperformance.com/bbc-heads-184.html

http://www.pbmperformance.com/store....randparent=339

[SCOTI]

Originally Posted by Desert1957

http://www.profilerperformance.com/bbc-heads-184.html

http://www.pbmperformance.com/store....randparent=339

No pricing on the Profilers that I could find on that link.
The Brodix listed on the PBM site site are $950 each + shipping so $1800 minimum. That's a little more than purchasing & rebuilding some 781's.

Go to Summit or Jegs & the typical price for standard, street use oval ports are around $850ea on up regardless of mfr.

[77BBGMC]

I looked at the receipt for the machine work and parts on my 781’s, I have less than $900.00 for the pair (that’s not counting roller rockers). I did the bowl blending and cleaned up the runners to save a little money.