Radiator?

[85K10]

I have a 1970 Malibu i will be putting a 400SBC in. Right now it has a 307. I was wondering what i need to change to put in a bigger radiator, and what size radiator is suggested.

[e3j1c1]

I had a 307 before I built my 350 and put it in. I did get a new radiator, but that was because I didnt want to take any chances with a 30 year old radiator. A bigger radiator is not needed for any variation of motor as far as i know. If you can get a bigger radiator to fit, and if it makes you feel better, go for it i guess

[85K10]

Well the 400 is in a truck right now with a huge 4 core radiator. The BB Chevelles must have came with something bigger than what the 307 came with, and If so would the BB radiator bolt into my car, or would I need new brackets, shroud, rad, support, ect?

[e3j1c1]

Ok, make up your mind, is this 400 a small block or a big block? You have mentioned both and Im getting confused...

Anyway, this might help.
All Chevelles 68-70 small block Manual trans had the same radiator. Core dimensions 20-3/4 x 16-1/8 x 1-1/4. The '68 307 Auto and the '69 350 Auto were the only two v8 SB engines 68-70 with different radiators. Since no chevelles came stock with a 400 SB (or 400 BB for that matter) we can only assume the 400 SB would fit in the same category as ALL 1970 SB engines (MT and AT). The reason that the truck radiator is bigger may be due to the transmission and the simple fact that a tiny radiator in a big truck may look odd. If all you changing is the engine I wouldn’t worry about it. Like i said, i pulled out my 307/Powerglide and put a 350/400 and all runs well with original style radiator.

If the engine is a big block, the radiator in the 1970 396 and 454 were the same one. SO, if you insist, get a 396/454 radiator for 1970 chevelles. It should "bolt" on (same radiator support on SB and BB), but the shroud may be different. The BB radiator cores were roughly 8 inches wider than the SB radiators'.

Hope that helps

[85K10]

Thats what I was looking for, thanks! Sorry, it is a 400SB, I was thinking of using a BB radiator for extra cooling.

Thanks again, Anthony

[ChevelleProSS]

More considerations: Many SB stock engines came with a stock 2 core radiator. Once your engine has been rebuilt, it is important to know the bore. Engines that go over .40 and .60 over will get hot quicker and require better cooling. Perhaps a simple solution is to get a 4 core radiator and a fan if you require more cooling. One must consider the inside surface area of a 2 core versus a 4 core radiaor, there is almost twice as much cooling off.GL

chevellepross