This question is for the guys running big blocks.
I have a pontiac 455 that I'm going to use to replace the 350 and I'm wondering what you guy with the big engines do for cooling.
The stock cruiser radiator just barely keeps up with the 350 in Moab and now with 100 cubs more how big of a radiator do I need.
It looks like I could fit an aluminum 19x26 double core without to much work and with a little trimming something a little larger what do you guys run?
The engine will be close to stock with just a very mild cam.
Thanks
Steve

Find the biggest radiator you an fit in there. IMHO, a stock LC radiator is not sufficient for a small or big block.

i've run a couple of cruisers with small blocks and stock rads and have never had a problem with them.
my best friend runs a healthy chevy BB with a full size rad from a chevy truck in his and it runs great, but he had to do some resious trimming to get it to fit.
if the engine you're putting in is close to stock, then why not just pump up the existing small block that's already in it? that'll give you more room to work with.
either way, i'd say get the biggest alum rad you can put in there and run a shroud. make sure the rad's not too wide or the tires will hit the tanks at full turn under compression.

another question. what transmission do you plan on running?

I'm going with the 455 for the low end I don't need the horsepower the 350 is sufficiant already but sometimes I need a little more in the higher elevations
I was actually looking for a 400 replacment but ran across the 455.
The engine external size is the same as my 350 so I figure why not.
I know a couple of guys on here run or have run caddy's what did you guys run.
To Orangefj45 I run a sm420

so will your bellhousing work on the 455? i guess it should, right.

Yes the bellhousing will work that's the nice part about Pontiac they are all the same from the 326 to the 455

my .02,
run a big radiator, like a aluminum 4 core, run a nice puller fan that has a realy good shroud that seals around the radiator. Try and keep all tranny coolers and winches out of the grill to let air pass through. thats what i learned after trying to keep 383 stroker cool.

There are a couple guys running 30" wide radiators but they hang past the frame just a little. Not sure if your tire will get up there but you might be able to build the mounting bracket to protect the side tanks.

I am running a bored high compression 454 in mine and I use a griffen 19x26 radiator with the ford conture fans. Still over heats a little on the extreme stuff. My problem is air flow. Radidator is bigger than the front of the truck so everything obstucks the airflow. Oh ya mine is Automatic too.

I tried a duel pass radiator and I did not work so well. Now sitting in the corner of my shop.

YOu have to do a few things.

First you need some airflow. All the radiator and fan in the world won't work if you keep all the pass-through air in the hot engine comartment. Stock louvers work, but cutting inner fender helps too as does raising the entire cowl portion of the hood 1/2" so air can escape across the entire width of the engine.

When you get the ratiator, make damn sur eyou have a TIGHT shroud. That is so important. if the fan goes below the radiator then get custom shrouding to keep that air pointed at the radiator.

I am running a bored high compression 454 in mine and I use a griffen 19x26 radiator with the ford conture fans. Still over heats a little on the extreme stuff. My problem is air flow. Radidator is bigger than the front of the truck so everything obstucks the airflow. Oh ya mine is Automatic too.

I tried a duel pass radiator and I did not work so well. Now sitting in the corner of my shop.

This is the reason my bezel is upside down... :D

Thanks fellas for all the info I plan on using a two row aluminum 19x26 radiator with a fan shroud and a 19 in with a thermo clutch, I now have a 19 in flex fan,
I was also planning on boxing in the intake side of the radiator, my motorhome uses sheets of rubber to seal off air gaps It looks like an easy way to go
I was hoping to hear from a couple of the 500 caddy guys to see what they are doing since the pontiac is a similar set up "long rod, long stroke" motors for tons of low end torque.
Thanks
Steve

Been running a 500 for about ten years in my cruiser. You"re on the only track that works. Everyone thought I was crazy with the cardboard taped on but the air that doesn't go through the radiator doesn't cool. Tight shroud is also very important. crossflow 19x26 from summit and a taurus fan.

I was also planning on boxing in the intake side of the radiator, my motorhome uses sheets of rubber to seal off air gaps It looks like an easy way to go



that sounds like it outta work really well.

floppy, do you have pics of this? thanks in advance


chris:cool2:

I use a 19 X 26 aluminum two row in my 454 powered Chevy II.
It keeps it plenty cool in traffic in the middle of Florida summer heat.

Hey Floppy.. instead of using cardboard.. we have used old conveyor belting, its pretty easy to come buy, and it comes in a lot of different thickness's .. some you can just cut with shears and others that are so thick you need a jigsaw to cut it, its easy to work with, and can take a lot of abuse.. most place's that use it have old rolls of it laying around and are more than happy to let ya take some of it..

no pics but I could take some

there is a two core out there that fits in the stock hole but it's gold plated!

Hey Floppy.. instead of using cardboard.. we have used old conveyor belting, its pretty easy to come buy, and it comes in a lot of different thickness's .. some you can just cut with shears and others that are so thick you need a jigsaw to cut it, its easy to work with, and can take a lot of abuse.. most place's that use it have old rolls of it laying around and are more than happy to let ya take some of it..

Thats a great idea, I could use some to make my tube fenders a bit more streetable. Guess I shoulda mentioned that the card board was only for R&D.