Thread: 402BBC - HEADS question any help appreciated.

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Are 6272292's and 3993820's same combustion chamber? Same head basically?
any body have info on them would be great valve sizes etc..

If so, my local machine shop has those two heads and he wants $40 for them magnafluxed, and cleaned.
What do you guys think

I don't know about mix matching them. I know the 3993820 head would be a good one to use, big ports, 113cc chamber. I'm not sure about the other one though.

Those should both be 2.07 intake and 1.72 exhaust valves.

I got mixed results on the 6272292 heads looking on the NHRA tech site.

http://www.nhra.com/tech%5Fspecs/classification/

For 1971: 300 HP 402's and 365 HP 454's - 105 cc.
For 1972: 210 and 240 HP 402's and 230 HP 454's - 105 cc.
For 1973: 215 and 245 HP 454 - 110 cc.
For 1974: 235 and 270 HP 454 - 110 cc.
For 1975: 215 HP 454 - 112 cc.
For 1976: 225 HP 454 - 112 cc.

Not sure how it lists as three different volumes, but I'm betting it's a 105 cc head.

3993820....71......oval...OPEN...402, 113cc chamber, 255/114 ports
6272292....70-78...oval...OPEN...402, 454
I found these results on mortec.com. im wondering whether 292 would be the same 113 cc. I'm assuming so, the heads look identical. At my local machine shop I ran apon a set of 215's, and I wanted to buy them but unfortunately they were customer heads! dang it, oh well. SOO... I bought the mix match heads. for $30 . which isnt bad. The guys at the machine shop were pretty positive they are the same.
I'll post some pics if you guys want of the heads

they are about the same head look at valve size .the chambers is the same some head had very small valves and rotators on intake and ex but not sure on the 820 to 292the 292 has rotators just on the ex side and takes a 2.065-1.72 valves

Originally Posted by pat mccarthy

they are about the same head look at valve size .the chambers is the same some head had very small valves and rotators on intake and ex but not sure on the 820 to 292the 292 has rotators just on the ex side and takes a 2.065-1.72 valves

Alright, also, I'm pretty sure on the 820 head, somebody wrote with a permanent marker 2.19/ 1.88. so Id assume they're cut that big. but i could be wrong, im trying to find more info on valve sizes for the 820 but no luck yet. I measured the middle groove of the 3 angle that is present on both heads, approximately accross. and both came up at 2 and 3/16ths. im not sure what that translates into decimals but. They appear the same, but i best bet bring em in when i get work done to them at the machine shop and have them fit a few valves to check.
im gonna deck them .005 just to be a straight head, new guides, 3 angle job, clean job.

2 3/16 = 2.1875" or rounds up to 2.19"

Originally Posted by Henry Rifle

2 3/16 = 2.1875" or rounds up to 2.19"

Thanks a lot Henry