Ok I tried searching for this question for a while and I couldn't find a direct answer my question is

How much horse power is the stock 305-z28 radiator rated for? At what point do I need a aluminum one ?

Also what is the stock clutch set up rated for also ??

Just doing some more bolt ons on my 290crate and wondering what I need to upgrade with a set of new heads on it

 

Any one ???

 

Isn't your stock radiator already aluminum?

In perfect, like-new condition, I'd guess your stock radiator and clutch are rated for ~230hp. That would be to run in death valley with the AC on in 120* temps. You do that much? The "limits" on such items are affected by so many criteria that you can't simply state that the rad or the clutch is "good to go @ xxxhp".

I've run a 350hp SBC with a stock 3rd gen radiator and most of the time, it worked great. Coming up out Vegas though (long climb) in 110* temps, my coolant reached ~220F; the system was at it's limit there. Had I down shifted out of 6th gear and run in any lower gear, the car woudl have over heated.

I ran a SBC400 @~300hp in a 3rd gen on a stock rad and it worked fine too, but I know that in "extreme" conditions, it would have struggled as well. Try it and see.



Same goes for the clutch. You can measure the tq the clutch can take and get a hard number, but hp? Totally depends on how you use it. Even with the stock engine, launching the stock clutch from 5k on slicks...it won't last long. Put a stock clutch on a 350hp daily driver and treat it with maturity and respect, and it could last years.

 

Yea I understand there are limits but I am just trying to figure out what I need to because I want to put some new dads on my 290 crate and I don't want it over heating or the clutch slipping so I figured do it all at once but no ever states oh around 300tq the clutch slips and 350 is pushing your radiator

I live in nj so I don't have to worrie about 110 120 degree weather often but we do hit the 90s and I don't want to be stuck on the highway in bumper to bumper with a over heating motor with aluminum heads on

 

I don't think there is a difference in the stock radiators, 305>350. In both the aforementioned cars, they were originally equiped with 305's; the first and '86 LG4, the second an '83 LU5. Both has aluminum radiators with plastic tanks, stock.

What is going to ruin your chances of running a stock radiator are;
1. massive drop in efficiency
2. SUSTAINED, output far above stock.

If you install a 400hp engine that has low friction, efficient heads etc, and run an efficient low rpm gear, it will work fine; Short bursts such as drag track etc. the cooling system has enough capacity to absorb the heat generated by the extra power, and expel later, and for general driving...it takes the same hp to move the car in daily driving, so assuming you don't have a huge cam wasting tons of fuel, lot of friction, high cruising RPM's, a stock radiator can work fine in MANY cases. I'd say that most times it fails, it's due to poor cooling system maintenance and not undersizing. In short, you can add more HP, b/c 99% of the time, you're not using it...and when you do, it's for what; 5 seconds? 10 seconds? The stock radiator could likely work fine in your situation.

Clutch too.

 

Ok cool so I just need to worrie about the clutch then

because I have te 290crate n I wanna put on 64cc heads and I have a ex268h cam in it and there was an artical that did the same thing with the same motor and cam and made 400 something tourqe and around 380hp so

I'm shooting for the same results hit trying to plan on what is needed I drive the car daily so yea Thats the plan right now

Thanks for all info I'll leave the stock rad for now until I get some extra cash to do so and I'll plan on getting a better clutch