Hello I have buick 430 with a possible cracked head But I know a person that can give me a great price on a 455 set of heads they are from a 72 455 riv. What should I expect I am pretty sure the install is the same right? Other than that should I expect other changes will the performance be better or worse am I crazy or did I at one time hear that 430 heads are better in flow than stock regular 455 heads. Any advice and or tips are very appreciated thanks, will
It will present some problems for you, the 430 heads have an oil passage in them for the rocker shafts, the 455 heads oil through the pushrods. You can swap over to the 455 style pushrod oiling if you want to buy the 455 lifters and pushrods, then plug the hole in the block that feeds the old 430 heads.
In A previous post yardley stated I thought that 455 heads need no changes on a 430 except for different size intake bolts. thanks, will
The 430 heads as stated above have oil holes drilled in them to feed oil to the rocker shaft. 455 heads do not have the oil hole and need to be used with 455 lifters, pushrods and rockers. Some guys have been able to use the 430 rockers with 455 pushrods and lifters, I am pretty sure that the pushrod ends on the 455 ones are too small to fit properly in the 430 rockers. The 72 heads present an additional problem in that they have holes for EGR passages that mate to the 72 intake. If these holes are not plugged, you will have an exhaust leak if used with the 430 intake. Many 400-430 heads did have cracking problems (have been there myself). It may be possible to clean the affected area and use a high temperature epoxy to seal the leaking area if it is not in a critical area. There are a lot of good chemicals out there today that may fix the problem. At least it can give you time to locate some good heads. The 70 or 71 ones would be a good choice if used with the correct lifter, pushrod and rockers. Good Luck, Mark P.S. and yes, 455 heads need 7/16 bolts instead of the 3/8 ones used on the 400-430 heads.
72 heads some 72 heads have antifreeze ports in the center of heads by combustion chambers that unless you can plug them will not work on a 430.try 70-71 heads the shouldnt have those holes. andy
