Does anyone have experience using 59 degree heads on a 48 degree block? I've heard it can be done but what is involved and is it worth it? All 48 degree R3 blocks are siamese bore and I have heard that cooling system mods are needed to keep them cool enough for street/strip use, I read how to build big inch small block mopars and he says to drill .125" holes between the cylinders to allow coolant flow but doesn't that defeat the purpose of a siamese bore? 4.600-4.22-.125=.255 is that bad? I suppose its better than individual .125" walls on a non siamese cylinder. The reason I ask is that I have a scat forged 416 rotating assembly and am tired of looking for a decent 340 block for $500 or less to replace the one I have that needs lifter bushing. The R3 block seems like a better investment, thanks in advance for your replies.
48 Degree R3 Block Using 59 Degree Heads?
- Thread starter LS1K5
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darndart
Well-Known Member
Check out the 340 resto block. It takes all stock hardware but is 4 bolt main & much stronger!
Pipe Dreams
Member
You can use a 48 degree head on 59 degree block, but not a 59 deree head on a 48 degree block. All R3 blocks are not siamese bore. You can get an R3 block 48 0r 59 degree with or without siamese bore.
My 340 resto block is is a 59 degree non siamese R3 block with the extra head bolts milled off. If you decide to go with the 340 resto, comp cams is the only one I know offering an roller lifter fits in this block and I have not heard good reviews of them.
My 340 resto block is is a 59 degree non siamese R3 block with the extra head bolts milled off. If you decide to go with the 340 resto, comp cams is the only one I know offering an roller lifter fits in this block and I have not heard good reviews of them.
tubtar
Well-Known Member
The big issue I see would be lobe placement with the different lifter bore centerline. You would need a 48 degree cam core with a 48 degree block , which is not exactly inexpensive. Then I don't know that the heat treat on most blanks or ground shafts that you might re-grind will allow for anything but what can best be described as a serious profile.
Can it be done ? Yes.
Should it be done ? Unless you are doing a real balls out effort ( in which case , you would probably want 48 degree everything ) , I like the resto block approach.
If you are anticipating more than 600 h.p. , then you certainly want to consider more than a production casting.
If you will be closer to 500 , a stock block might be an attractive alternative. If you have to prep a stock block , it isn't cheap......but prepping an R block isn't either. Stock block would be cheaper , R or resto would be stronger.
Add up what each would cost with machine work , factor in potential re-sale and the decision makes itself for me.
tubtar
Well-Known Member
Another consideration with 59* heads on a 48* block would be pushrod clearance. Off set rockers and lifters ( you are stuck with rollers here ) would make it possible I think.
But you are knee deep in " Why would you want to ? " territory now.
But you are knee deep in " Why would you want to ? " territory now.
Pipe Dreams
Member
Just got to thinking about it alittle bit. I'm sorry you are tired of looking for a decent 340 block for $500 or less, and you don't want to spend the money to bush the block you already have. BUT, both of these option are a hell of alot cheaper than buying a brand new block.
So I guess my question is, what is the purpose of this build? Max Hp or Budget
waggin
moving on ain't easy if you drive a Ford :p
I wouldn't sell a stock block needing machining for less than that...then again I'm not offering any up for sale either..if yur goin racing ya gotta ponyup the $$$$
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