[obengston]

I'm currently considering converting my 383 over to a 496. My question is I have read that you have to change the heater core.. Why?? Mine is a 68 Camaro, that had factory air. I removed the factory air box, and put a ac delete box on. The 2 heater hoses/tubes exit the box (one inside the fender, the other just outside the fender well). Neither one is next to the engine. So do I need to change the heater core if so why? Attached is the New 383 I'm thinking of replacing it puts 390hp to the wheel through a auto , and 560 on the bottle (dyno guy did a reverse pull and said I have about a 33% drivetrain loss), but I'm thinking I can get over 500 hp with a BBC. I don't know

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[Steiner]

No, you're OK. Non-a/c SBC heater core is right behind the head and valve cover and is a poor location as is. BBC shifts over another inch.

[obengston]

Sounds good to me. So basically i will only need to change motor mounts, and stands, headers, and I'm guessing a different tranny cross member?

[Steiner]

You got it. And radiator shroud, accessory mounts, pulleys if you're going to reuse stuff.

[obengston]

You say pulleys if I'm going to re-use stuff. So I can use my what: Alt / PS thats about it correct. Water pump is different correct. So the pulleys thats on the alt/ps want work with the bib block stuff?

[97Z4C]

bbc water pump of corse===change bracket on p/s pump to bbc and alt brackets-

[obengston]

Sounds good. Appreciate all the info. Hope to make it as easy as possible.

[Eleanor's Nemesis]

Originally Posted by obengston

Sounds good to me. So basically i will only need to change motor mounts, and stands, headers, and I'm guessing a different tranny cross member?

Hey oscar, I hope all is well.....you will probably want to change the front springs too, especially if you use iron heads.

[scruff737]

I'm not sure about a 68..but on my 69 I had to get the BB radiator along with the shroud.

You may also need the proper crossmember since the frame mounts shift the BBC over a bit.

Probably a couple other things I forgot too...

[obengston]

I have been thinking about the springs, figure I may need to upgrade them. Right now I have the QA1-Coil overs, I'm not to sure about all that weight being supported by the shock mount area!! I'm sure there is a way to reinforce that spot, or change to a different set-up or go back to a regular spring, and shock. Anyone have a suggestion??

I'm using a electric fan with aluminum radiator so hopefully I want have to change that.

And I have heard something about possibly needing a new trans cross member...

[PowerWindows]

As the engine is moved 1" or so to the right (pass side) due to clearance issues the tranny is also moved a corresponding amount to keep the engine/tranny parallel to the car so yes, you'll need a different tranny mount.

If you still have mechanical throttle linkage you'll have to switch to a BBC linkage also.

You'll also need to shorten the driveshaft.

[obengston]

Copy on tranny cross memeber, as far as throttle I have the lokar cable so I should be good there at least.

[TJS69]

A Big block is only moved 1/2" to the passenger side. If you measure from the air cleaner stud it is 1" closer to the RH fender than if you measure to the LH side fender.

You must change your transmission crossmember ! The transmission mount is not only 1/2" to the passenger side, it is also 3/4" forward of the smallblocks location.

If you try to use a one bolt transmission mount or a small block crossmember, your engine will not sit straight and your headers won't fit etc. This also can cause a vibration or other driveline problems.

Your heater core. If it is a small block non-a/c car your heater core outlets will be behind the passenger side head if you install a big block. On a small block a/c car your heater core is fine. The outlets are way under the fender. The problem is the a/c Evaporator core will be hit by the engine. Factory Big block a/c cars changed the angle of the a/c housing so the engine would fit !

If you are using an a/c delete cover, you will be fine. The a/c evaporator is gone and you don't have to worry about it.

ALL pulleys and accessory brackets are different between the small blocks and big blocks They are also different between a short water pump and a long water pump ! There are 4 different sets of pulleys ! 5 if you count the six cyl.

They are :

Short water pump (67 - 68) Small blocks.
Short water pump (67 - 68) Big Blocks.
Long water pump (69) Small blocks.
Long water pump (69) Big Blocks.

[prostreet69camaro]

You did not say what transmission you are using. I reused my crossmember that I had on my smallblock. I have a turbo 400 transmission. I also have the big block engine stands.

[TJS69]

Originally Posted by prostreet69camaro

You did not say what transmission you are using. I reused my crossmember that I had on my smallblock. I have a turbo 400 transmission. I also have the big block engine stands.

The reason that this worked is because, your transmission crossmember was made for a big block and is already offset. Chevrolet never put a TH-400 behind a small block. Meaning you originally had the wrong crossmember, but now it is right !