65 396 radiator on L-75 car

[John C.]

Hey fellas, just wondering if there would be any issues installing a 396 / L88 radiator on a small block car with A/C. I found a NOS 396 Harrison ( still boxed ) and thought I may be better off with it than an aftermarket Dewitts made for a 300 / 327 A/C car. Is the 396 radiator larger in capacity and cooling ability than the small block A/C radiator ? The current radiator does fine, even in hot weather UNTIL the A/C is turned on, then the temp shoots up and takes a while to come back down, even after the air is turned off. I've tried to determine if the clutch is working properly and I'm not 100% sure that it is. One would think that if the clutch is the problem, the engine would heat up in slow traffic, esp when it's hot outside, but it doesn't. I rarely run the air, and only do a couple hundred miles a year on the car, I just want everything to function properly. So, it's either a NOS Harrison 396 radiator that is GM correct for a big block car, or a copy radiator by Dewitts made specifically for a 300 / 327 A/C car. Any suggestions ?
JC

[Patrick H.]

Re: 65 396 radiator on L-75 car

No question. I'd go with a new DeWitts. You have no idea what the inside of that allegedly NOS radiator looks like, and it could be a $1000 crap shoot.
Let someone desperate to have a 396 radiator buy it for his car.

[John C.]

Re: 65 396 radiator on L-75 car

Thank you Patrick !
JC

[Wayne M.]

Re: 65 396 radiator on L-75 car

The original 396 rad is approx. 2 inches wider than the small block rad; doubt it would fit the C60 rad support. Besides, there's enough plumbing already on the pass. side, especially if you're talking '64-5 air cars.

[Paul S.]

Re: 65 396 radiator on L-75 car

Buy the repro, i agree with pat

[Mike T.]

Re: 65 396 radiator on L-75 car

John - DeWitts does offer one that still fits the smallblock radiator support but the tubes are a bit bigger than the standard replacement radiator, 1 1/4 tubes. I added one to my L75 65 Coupe since I will eventually add a Bigblock. The part number for this upgraded core is #1149063. As with all their direct fit radiators, it's also available with the Black Ice coating.

[Joe L.]

Re: 65 396 radiator on L-75 car

Thank you Patrick !
JC

John------


One other possible problem: I don't know if there exist any molded radiator hoses that would work for a small block with the L-78 radiator. The only ones that MIGHT work would be the L-78 radiator hoses. If those don't work, then there are none that will. That would mean using the "accordian-style" "universal" hoses (YUCK).

[Jim L.]

Re: 65 396 radiator on L-75 car

I use a 396 radiator to cool the small block engine in my vintage racer.

The stock, lower radiator hose for a small block application fits and works just fine.

For the upper hose I use a quasi-generic molded hose from NAPA which has a single bend, like the stock small block upper radiator hose. This hose is a little longer and would fit a small block with small block radiator if you trim it slightly. I use most of the as-manufactured length in my application. The thermostat housing angles towards the driver's side and the 396 radiator has the early straight inlet fitting.

It all looks like this:



The only issue I had with this installation centered on the reproduction 396 radiator support. The two bottom brackets were in the wrong location. Fortunately(?), the spot welds were pure junk and it took 30 seconds to pop the brackets off and only slightly more time to weld them on in the correct location.

There is a Harrison oil cooler ahead of the radiator. The overall cooling system keeps the engine at or below 180* lap after lap after lap.

Jim

[John C.]

Re: 65 396 radiator on L-75 car

Outstanding responses guys. I for sure don't want anything that won't fit the stock small block brackets. Glad to know about that Wayne, thx.
I'll go with the Dewitts. BTW Mike T. , since you apparently have experience with the Dewitts radiator, what should I ask for to get a finish that will appear as close to the OEM as possible ?
JC

[Patrick H.]

Re: 65 396 radiator on L-75 car

DeWitt's own website states that the Direct Fit replacement is less effective than the original style:
" While its BTU rating (4100) is slightly less than the original, it is still 25% better than the copper replacement radiators"

http://www.dewitts.com/collections/corvette-aluminum-radiators/products/1963-1972-aluminum-radiator

Buy the original style one from them if you're truly concerned about overheating.

[John C.]

Re: 65 396 radiator on L-75 car

Yeah, overheating is a concern, esp since the car has A/C. I'm in the Memphis area ( yep, hate it here ), the humidity is aweful and summer temps are high, although I rarely get the car out if it's that hot. That's what got me interested in the BB radiator in the first place, but now that I'm aware of the fitment problems, I'll stay with an OEM replacement. Thx Patrick !
JC

[Mike T.]

Re: 65 396 radiator on L-75 car

John - I've ordered DeWitts Direct Fit replacement radiators for my 61, 65 and 66 Corvettes and as far as I know the only choices are natural aluminum or what they call their 'Black Ice Coating' which is what I specified. They do offer the more expensive 'Restoration' radiator which is the original stacked plate look and I believe those are available only as Black but you'd need to contact DeWitts to make sure. Here's a couple pics of the slightly larger core Direct Fit radiator in Black Ice I used in my 65 Coupe.

[John C.]

Re: 65 396 radiator on L-75 car

Great pics ! I'll go Dewitts for sure. Any tricks you could share to make the job as easy as possible ?
JC
OH, antifreeze choice ?

[Richard F.]

Re: 65 396 radiator on L-75 car

The mounting pins on the bottom of the 396 radiator are in a different position than those on the small block aluminum radiator.

[Joe L.]

Re: 65 396 radiator on L-75 car

The mounting pins on the bottom of the 396 radiator are in a different position than those on the small block aluminum radiator.

Richard--------

It's hard to compare the positions of the pins on the bottom of the GM #3155316 radiator (small block) and the GM #3007436 radiator (mostly big block) since the radiators are of different widths. However, the placement of the cupped mounts welded to the bottom of the radiator support are shifted to the right by 3/4" on the big block support. The actual center-to-center spacing between the pins is the same for both radiators---11".