My chevelle came with this engine and I would like to rebuild it. Is it a good block to use as a starting point or do they not make good performance builds?
I always come across people saying to use truck rods, are the ones in this engine the rods they are refering to? Or are they not worth reconditioning? Im looking for about 500HP and TQ, nothing extreme but something with some grunt and need some cheap(er) parts, and would like to work with what I already have.
Thanks for your time,
Shane

Shane,
The basic engine is a very good foundation for a street or mild race performance build. The heads are not very good for performance use and would probably not be worth spending any money on, depending on how much additional power you are looking for. It probably has a cast crankshaft which is fine for most applications.

Just depends on how much power you are thinking of making.

Bill,
Thanks for your response. Considering the things I need to accomplish with this car I need to cut some corners. I feel 500HP/TQ will suffice as well as lower the cost of the rebuild. I also need a new tranny and rearend so I would like to limit the HP levels for now to allow me replace these and not require me to go all out.
I would like to use the block, crank and rods, bore it over and thats it. What do you think the HP limit is with these rods? Could I meet my goals with them?

Rebuilt 3/8" bolt truck/thumb rods with new stronger aftermarket bolts are fine!!

Post back the last three numbers of the heads casting numbers and we will try to tell if you have the smaller, less desirable peanut port heads or the better true large ovals??

Another way to do this is, are the intake ports wider than they are tall, if so, they are peanut port heads!!

And it's not that PP heads ARE bad, it's just that they have almost SB heads sized intake ports so they just don't breath even after being extensively worked over much above say, 45 to 5,000 rpm.. MAYBE 5,500 rpm on a 396/402/408 motor...

BUT worked over, they STILL create a BUNCHA lower rpm torque!! (Imho)..

You can do a couple of things head-wise here if you want to use GM heads.

Stay with a flat-top piston and use .020" thick shim headgaskets and a head like the old -206 at from 96.+ to 98 cc's or a -215 head at about 100/101 cc's OR use an open chambered head like a -781 or -049, (anywhere from maybe 112/113 to above 120 cc's), and low domed pistons and shims so that you create right at 9.75 to 1 CR. so you can run decent pump gas!!

BUT you really need to cc ALL BB heads b/c they vary a lot so that you will know what your CR. is!!!!! And try to run a quench from say .035" to .045" for best chamber eff.!!

pdq67

A friend of mine just purchased a 1970 chevelle with a 454 from a 1986 blazer.

The motor has a little knock, so he wants to get a total rebuild on the motor.

A few people have suggested that he purchase a 1970 block, then get the 70 block rebuilt.

My question is, what is the difference if you rebuild a 1986 block or a 1970 block? If he uses performance heads, crank, piston, etc.

I do understand that the value may increase if the motor is a 1970 motor in a 1970 car. But, besides resale value, is there any difference between rebuilding a 1970 block vs a 1986 block (as long as you use all the same performace parts)?

But, besides resale value, is there any difference between rebuilding a 1970 block vs a 1986 block (as long as you use all the same performace parts)?

No.Nothing wrong with a 1986 454 for a performance build.

It just make's some people think that it will be worth more money if it has "close" to a numbers matching engine in it if it doesn't have the original engine in it is all.

pdq67