I have a 68 GS400 conv. Will the intake from a 400 fit a 455? Will a 455 bolt up to my tranny? Anything else that I would need to be concerned with mounting... ...exhaust, radiator, motor mounts, ???
The parts on 70-72 455's will swap to a 400-430, but 400-430 heads oil through the head rather than pushrods. Intakes swap with no problem.
The intake will swap if you do not have the smog heads with the extre holes in them. If your heads do have these holes you will have to plug them or you will have exhaust blowing . I have a 68 GS 400 and did this swap. This is very easy because all the brackets and tranny bolt right up. If you only have the 2 core radiaytor as i had you should get a 4 core. I am running a reconditioned 3 core and get by with it but a 4 would be better. Ed K
68 GS Thanks! I am thinking of putting my numbers matching 400 on a shelf and drop in a 455. As you probably know, any information is beneficial and greatly appreciated. If I do the swap, I would like to install my Edlebrock Performer intake and Edlebrock carb on the 455, and then put the original intake and carb back on my 400. I am also considering installing a 200-R4 tranny and 3:42 posi... But, I would need to buy them first. Again... Thanks for the info! Gil - Mpls. MN
I did that with the 67 4 spd I had a few years back. Took a low mileage 70 electra 455 block added a GSCA cam (don't recall which one, I think one above stage 1), rebuilt my 67 heads with new springs, used the 400 intake and vuoilla, instant 100+hp increase that looked completely stock.
455 into '68 GS400 I have a .030 over 455 in my '68. Everything is a straight bolt up. If you use all of the 400 accessories, nobody can tell the difference. You need to keep the crank pulley/alternator/air conditioning/water pump matched. The later big blocks used a longer water pump which doesn't line up with the early stuff. it also makes it hard to get the fan shroud off the car with the water pump in place if you use the long version.
