Valve size/rebuild
- Thread starter 39 STD
- Start date
Karl Wolf
Well-known member
Read JWL's book, "Flathead Facts".
I think I know a bunch, the book showed me quite a few things...
Red, hisself, sugested a fairly mild cam for my 265 flatty... I like it.
Your stock size 1.5 valves are hard to beat- when you put in bigger you run the risk of robbing from some other aspect relating to performance... And, you have to do a bunch of work to make them an advantage- and that is only possible to find that at real high rpm...
That being said, Chev small block exhaust valves do well with a reground cam...
Karl
I think I know a bunch, the book showed me quite a few things...
Red, hisself, sugested a fairly mild cam for my 265 flatty... I like it.
Your stock size 1.5 valves are hard to beat- when you put in bigger you run the risk of robbing from some other aspect relating to performance... And, you have to do a bunch of work to make them an advantage- and that is only possible to find that at real high rpm...
That being said, Chev small block exhaust valves do well with a reground cam...
Karl
Brian
Well-known member
I think, for the build you're planning, just use stock valve sizes. A lot of work to install bigger valves, and you'll not see any gain in performance. The same money could be spent on other mods for more gain in performance.
Now....if you were building up a big displacement, money no object, every conceivable modification type engine, I'd say sure, fit bigger valves, but on a little 239, I repeat, you'll not see any performance advantage.
Now....if you were building up a big displacement, money no object, every conceivable modification type engine, I'd say sure, fit bigger valves, but on a little 239, I repeat, you'll not see any performance advantage.
BILL WZOREK
Well-known member
Ok Karl
This may be a stupid Question but I will ask any how {may be there are other new " B's " that may be afraid to ask } are the ch**y exhaust valves used for both intake & exhaust in our engines
(see this new " B " learned on here it's not a motor ) LOL LOL
THANKS
BILL W
This may be a stupid Question but I will ask any how {may be there are other new " B's " that may be afraid to ask } are the ch**y exhaust valves used for both intake & exhaust in our engines
(see this new " B " learned on here it's not a motor ) LOL LOLTHANKS
BILL W
Russ/40
Well-known member
Ok Karl
This may be a stupid Question but I will ask any how {may be there are other new " B's " that may be afraid to ask } are the ch**y exhaust valves used for both intake & exhaust in our engines
THANKS
BILL W
Yes
Ol' Ron
Well-known member
If you send more time here you'll findout that the SBC valves are used in allot of flathead applications and offer a number of benifets, but can't be used in a stock engine without difficulty. The stems are .060" longer which make them desireable for Hi Lift cams with smaller base circles. This has allot to do with adjustable lifters. To use the adj lifters yoou must drill the lifter bores to hold then while adjusting. With a stock cam you have to remove some material fron the lifter adj bolt or the valve stem. It's best to find a machine shop that has some experience with Flatheads.
