Hi all
Im not having a lot of luck finding the 829 4BBL castings... I have the 2BBL low compression heads and was wondering what I could safely mill them down to? Id like to get as close to 10.25 to 1 as possible but figure that gaining 1.5 points with milling and a shim type gasket probably isnt going to happen.
Tony, What piston are you planning to use ? ( ") down from deck ? Gasket thickness ? Willing to deck the block ? I'll check my horde, for that #. Cheers, roverman.
I want to use the stock flat top pistons..I could go with a copper shim gasket. I would be willing to deck the block.
D&D has a useful chart on head cc's and compression. Olds 2 barrel has 51 cc compared to Buick 300 54 cc. I would take .030 off the heads and deck the block.
http://www.aluminumv8.com/tech/tech.htm
Thanks JIm.. The 829 castings are the 43 CC heads.. They show the *749 2BBL castings as being 51CC's..
It could all be done Im just not sure. I just dont want to muck up that $$$ Willpower intake to make it fit on severely shaved heads.. Eventually I might get the stroker engine done and Id hate to have ruined it for fittment on that engine.. Sometimes this stuff is like a circurlar firing squad LOL
I think you should just try to be patient. The heads you want will turn up. These engines have been squirreled away under workbenches and in garden sheds all over the place. Post "wanted" ads. Mention your quest to old-timers at car shows. Call independent machine shops, and ask if they know of someone... They're out there, and when you find them they probably won't even cost much.
Some deck improvement can be had by lengthening the rods. Find bushings in an appropriate size, bore the rods offset to the top, then install bushings and bore for maximum length. If you use small journal, smallblock Chev rods, they are already longer. I forget the exact amount of length you gain, but it is something like .060 in.
Larry, .040 longer. Buick/Olds/Rover 5.660,SBC small journal stock length 5.700.
Im beating the bushes Curtis.. ;-)
I guess this discussion brings up another point.. How well do the production valve seats hold up in the older heads with unleaded fuel?
I never found the seats to be any problem.
I've heard warnings about milling too much off the heads though, and the decks don't have any too much thread for the studs in my opinion. Wasn't there a small chamber Rover head? That'll fit the Olds block without any trouble. Just have to use the Rover rockers and valve covers. Which I realize can be a hardship what with being cast aluminum and all. ;-)
If that doesn't work or you like the Olds look, you can also use the Jetfire heads. They are the same compression as the 4bbl heads and sometimes seem easier to find.
Jim
JIm From what a local Jetfire expert told me the Jetfire also used the *829 casting.. (10.25:1 C.R. for '61-'62 4 bbl auto and manual cars, '63 4 bbl manual cars).
The high compression (10.75) * 534 heads were used on the '63 4-bbl automatics only..
> Wasn't there a small chamber Rover head?
Yes but those would put the compression ratio well over 12:1 with the flat top Olds pistons. Standard Rover or Buick 215 heads will still be higher compression than what he's shooting for, though you could use the thick composite head gasket with the standard Buick/Rover heads and maybe be in the ball park (I'd need to run the numbers to verify that).
Dan Jones
The Rover heads are between 28 and 36CC's... Id have to go with a dished piston since I like to keep quench tight on anything I build.
Might want to run some of those numbers to see if there is a better solution. Here's a good shot of various heads:
http://www.roversd1.nl/sd1web/capacity3.html
If you look at the Olds head there is going to be some squish but not a whole lot. Also, see the squarish lugs in the chamber of the 300 Buick heads? I could swear my Jetfire heads had those same lugs. I had a talk with Phil Baker about them and although they are the same CR as the 4bbl heads (within 1/4) I don't think they are the same heads.
I do agree with running dished pistons, but if you do that you might as well pick the heads you like best and have the pistons cut to match.
That photo is not all inclusive either.
Jim
I suspect the "lug",is to start the spark bubble, to a faster burn ? Even though the olds heads reportedly have the valves, closer to center of the bore, hp for comparable build, to the Buick/semi hemi, was near identicle. Perhaps because Buick had better burn/swirl and turbulence properties ? I suppose it's possible, BL could have bought the Olds design-but didn't ? Cheers, roverman.
The lug or dimple in other heads is just to help hold the head for machining. If you remove it you will have better swirl in the chamber, You would have to mill the heads .030 to compensate. The small chamber Rover heads are probably 3.9 heads milled down also. I could see where excessive milling would thin the head deck and make it more prone to cracking and warping.
http://www.v8buick.com/showthread.php?264142-What-is-the-purpose-of-these-raised-areas-on-the-Buick-350-heads&s=e638ac9463b3c63e7a841c209a2aa067
Still beating the bushes... Nothing yet
Tony, "If" I don't have the heads, I'll sell you new dished/Buick Silvolites, for $100. Cheers, Art.