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Author Topic:   Building A Monster
posted February 28, 2001 07:41 PM
I believe a 410 is what you get when you wear out your 406 with .030 over holes and need to bore it .010 more.

posted March 01, 2001 09:27 PM
There are a lot of combimation that will get you to any cubic inch.......and track size, car weight, and driver input need to be taken into consideration. BUT, for the stuff you are reading about, the standard 434 is a 3.850 stroke with a 4.155 bore.
You should never bore a hole more than .030, they become too weak and flex under pressure. this is how people BLOW a cylinder, they accually blow the side of the bore out because it's too thin.
You can build a stock block to 434 cubes any more would require a after market block.
You would need to raise the cam location to get the rods to clear the cam with a bigger stroke, and you would need a after market block to bore more than the .030 safely.

dirt mod 70
posted March 05, 2001 09:45 PM
434= 4" stroke .030 over bore on 400 block
421= 3.875"stroke .030 overbore on 400 block
410= 3.80"stroke .030 overbore on 400 block
I've run all three....421 is the best combo with-out to much grinding on block for clearance...still need small base circle cam

posted March 06, 2001 12:52 AM
Jeff have you Thickness checked the .040 over 400 blocks with ultrasound? If so what kind of measurements did you get? I ran a .040 (395) for five years and it did crack at the upper wall between 3&5 but that was from way too much heat from my first alky experience running way too lean. I know some blocks are better than others because of core shift. I still have my pistons and they are still look good so when I wear out my 393 bores I was planning on trying it again.

posted March 06, 2001 07:09 PM
Look at the Crower stroker rods.Real strong and alot less grinding in the block.

posted March 07, 2001 04:13 PM
roadhzrd, sorry about the email........i clicked on edit message and had it all typed before I knew it.......i didn't what to retype everything.......but i don't know how to cut and i tried to mail the thing to you that way........SORRY

Anyway on with the show, When I build a motor I order a good crank kit and .030 after a year or two I will order another crank kit that is basically the same .....
If the bores are wore out, order a new crank kit with a little less compression but .040
then put this in the old block.......get the gram weight of the pistons and pins you have now.........then when you order the new kit you can order a little thicker pin to balance up the recipicating weight. Use the old block, new .040 pistons, old rods and crank.........then put all the other stuff into a fresh block........
We have done this for years, we order kits so if and when we lose one piston we have spares on our shelf, some will be .040 but by doing this we have gotten twice as many shows out of a block and twice the life from our crank kits........
The big deal is to take apart what you have before you order the new kit, you need to decide if you have a splayed cap block, maybe you want to leave it a .030 over and just order another .030 and build a whole new motor, you need to see what needs less clearance and build around do that you need to know what wore out the pistons or the block.......
if you go to .040 just drop the compession to 11.5 or less..........again you can do this with staying with the same piston builder, just a little different wrist-pin to balance the whole thing back up right ....without the cost of balancing the assembly

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