455
- Thread starter fdcutlass
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86-blk442 said:
Frame mounts are the same and the engine mounts are the same as the stock 307. Drop in and go.
Biggest issues with fitting the BBO is the heater/AC box clearance as well as header fitment. As mentioned, clearance issues with the heater/AC box will be dependent on the condition of your body mounts. In my case, I had to cut, trim and fiberglass clearance in the box for room.
Headers are available for this swap and come in a few different variations. Cheapest (but still in the $400-$500 range) are the Hooker engine swap headers. However these have one tube on each side that actually runs into the wheel well, wraps around the frame and then comes back in to meet up with the other three tubes at the collector. Fine I guess for a drag oriented car but if you want to run normal size wheels/tires or something wider then you'll be smacking those tubes when turning.
The more expensive ($650+ uncoated) would be Kook's (now Dick Miller) headers. These fit inside the frame and are beautifully made. I have a set of the 2" primary/3.5" collector headers on my 455 and they fit great. Tight but still fit.
But with all that said, if your looking for mostly a good street performer then a set of reproduction W/Z exhaust manifolds will work perfectly and are much less of a headache than headers.
As said above the frame and engine mounts are the same as a 307, I currently have the hooker engine swap headers and you basically cant run anything wider than about 5 inches, I had to go with the 3.5 inch pro star to clear the header becasue of the tube being on the outside of the frame. As far as cost a 455 is no cheaper or more expensive to build than a 350. Most things will work on both engines including cam, lifters, oil pump, oil pan, carbs, valve covers, timing chains, etc, the things that won't work are the heads (bigger cc chamber, they will bolt up and run however), push rods (taller deck=taller pushrods), intake, crank, rods and pistons. A 455 with a normal intake will also fit under a stock hood, I have a torker on mine and I made my own frame mounts and it still fits under the stock hood, barely but it does. The valve covers on a 455 will clear the a/c heater core duct work on the pass side of the engine compartment, the problem is when you get into the taller valve covers then they won't clear and as stated above you can always cut the box and flip it over and refiberglass it in to make it work or they make block off plates for it. The other thing to think about with headers on a 455 is you will also need a dual hump crossmember and a better exhasut. Good luck on the build sounds like fun! 
Good to know all the info about the headers, Thanks guys. Great news on a 455 for me though, I found one that has about 10k on a rebuild that is a 1970. From what im reading this is a 10.5:1 compression motor with 365 stock hp, is this right? He did tell me he put flat top pistons in when he built it. Even if not i think im gonna buy the 1970 because I know the guy that rebuilt it and he only wants $500 for it and it runs!!!!!!!!!! He also said he will help me with getting it all set up and tuning the carb for it. Even better he has a transmission behind that was built at the same time that has a shift kit in it. Thinking he wants $400 for the transmission which is a good a$$ deal also. He told me this 455 is torquey as hell, and he also has a 425 he might would sell. Oh man am I getting excited, I think I can have this engine swapped before the snow melts and be able to enjoy it all summer long.
Just check out the block number and the letter on the head, should be E, I believe. Get ready to beef up your trans and maybe rear, due to about an extra 250+ ft/lb. What trans are you running?
I would use your TH350, you could get the TH400 as a back up. The Monte SS rear will help eliminate the exploding spider gear problem, it being 7 5/8 vs 7 1/2.
Saves you cutting the diveshaft. Depends, if the TH350 has good parts, it will last, if not horribly abused. Are you taking it to the track with slicks?
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