titeride85

I have heard about chevy 400s having overheating problems. I want to know if these are true or not. I am reconsidering the 350. I originally wanted to build the 400, now i have the option to pick one up.

I want to be sure what the deal is. are the 400 and 350 castings different? i have been told the waterjackets are smaller so the bore could be larger. is this correct or are they the same casting?

I REALLY REALLY NEED Knowledgeable people to respond.

Thanks in advance.

Desert86Roc

Because of the size of the bores, 400s do not have a waterjacket between the cylinders. There are "steam holes" that have to be drilled in the heads to eliminate pockets of steam/air and help with cooling these areas.

400s do run a little hotter than 350s, however, there are many, many 305s and 350s that run as hot as my 400.

My stock cooling system was not up to the task of cooling the 400 when the outside temperature gets over 100*. Anything below that and it was fine, in or out of traffic. Even with an Edelbrock Victor series waterpump, a tranny cooler and lower fan temp operation, my 400 still runs in the 230* range. With the AC on and on a 115*+ day, things really get cooking...but with synthetic oil, it should be no problem running that hot, but I dont make as much power.

I have since ordered a custom aluminum radiator that I believe will solve my problem above 100* and allow me to run my AC anytime.

Cuno

another problem with the 400 isif it does overheat, because of the fact that there is no water jacket between cylindars, they are more prone to crack than a 350.

The only reason I can think of to go with a 400 over a 350 is for the low end torque gain that would be desired at a drag strip. The H.P. curves are almost exactly the same.

If you do go with a 400 be sure to upgrade your cooling system as mentioned. I can imagine that you would have a lot of probs with a stock Camaro cooling system set-up.

RB83L69

I've had quite a few of them in various vehicles over the years, worked on a few for friends, etc..... never had any sppecial cooling problems with them.IMHO it's all a bunch of myths. Notice how they usually start out "I've always heard that...", spoken by people who have never had one. In general, any car with a poorly maintained cooling system will have cooling problems, and any car with a properly maintained one won't, no matter what size engine is in it.

350 and 400 castings are substantially different. One superiority of the 400 is that the cylinders are all one big piece, i.e. they can't move with respect to each other.

Get the motor if it's any good.

T-Tops

I've been running a 406 in my 87ta for a couple of
years now and had to do some mods to the cooling system.Such as, a griffen rad.,high flow pump, and replaced my old air dam on the car. I live in Florida so it stays in the 90's most of the summer.My car generally stays at 190-200 during this time.Thats with the fans running constant. I would recommend the 400, have had alot of fun with mine and not everyone has one under their hood...