jo75olds

Ok, well I am in the final stage of my 455 engine sawp

I am coming form a 350 but I wanted to ask if any one knows the height difference between the 455 and the 350 (using the 350 engine mounts) Just want to see what I am in for before I pick out a intake manifold

Thanks,
Jim

ah64pilot

I can't answer the height question but I would like to pose another one; are you using the 350 frame mounts to bolt your 455 rubber mounts to? I'm not saying it can't be done as I did it on my first 350 to 455 swap. It wasn't until a year later that I realized there was a difference in the 455 and 350 frame mounts.

I remember having a heck of a time getting the holes to line up. I eventually got them to fit by MAKING them fit. After about a year the rubber mounts were barely holding together. They were preloaded when I MADE them fit and the rubber ended up tearing after a while.

I would invest in the 455 frame mounts so that you don't go through engine mounts like I did.

TripDeuces

The simple fix from my understanding is to use the frame mounts and engine mounts that are the same: SBO to SBO, BBO to BBO. If you use the original small block mounts both frame and engine you should be fine. Doing a search of this sight for mounts should bring up several topics on it.

ah64pilot

Yeah Trip, you're right. I remember finding out about that now. The only question I would want to know is whether or not the BBO mounts are bigger (stronger) than the SBO mounts. There has to be SOME reason they made both. If the BBO mounts are stronger I would use them because these torque monsters like to go through the rubber mounts fairly quickly if you race them with any regularity.

don71

Its been awhile since I swapped but I think it was around 1-1/2" to 1-3/4 difference. I used SB mounts and frame pads with my 455.

If you have an OAI hood and air cleaner you will run into problems trying to use after market intakes. If thats not the case, you shouldn't run into too many problems. My example is a torker and a stock air cleaner. At least one inch of clearance with the standard hood. No problem on my end.

The crankshaft center line stays the same, regardless of which mount you use. As long as the right combonation is used like whats allready been stated.

joe_padavano

The BBO deck height is 10.625", the SBO is 9.33". That's 1.3" difference. This is where trig comes in handy, since a 1.3" difference in deck height (defined as the distance from the crank centerline to the deck surface) translates to a 0.9" difference in intake manifold height. Of course, this is not the difference in the carb flange height, since the details of the intake manifold design will change that. The Toro intake, for example, has a depressed carb flange. Aftermarket intaked can have a raised carb flange.