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148 bbc heads

Frankenblazer

Frankenblazer

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As most things on my 86 blazer ,totally mismatched, my block is 71 to 80 replacement engine, my heads 3933148 seem to be out of 69 396/427 truck
My question is are these heads any good? if not what heads cam combo should I get . I have 4,10.3/4ton axles 454 th350, I'm hoping for 500hp range, it's my daily driver occasionally off road,I was told originally it was 500 HP but I sincerely doubt it
 
Frankenblazer said:
As most things on my 86 blazer ,totally mismatched, my block is 71 to 80 replacement engine, my heads 3933148 seem to be out of 69 396/427 truck
My question is are these heads any good? if not what heads cam combo should I get . I have 4,10.3/4ton axles 454 th350, I'm hoping for 500hp range, it's my daily driver occasionally off road,I was told originally it was 500 HP but I sincerely doubt it
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Those should be oval ports, which suits your application perfectly. But more importantly, the rest of your combo needs to be matched. They would be open chamber heads which might require the pistons to have a small dome to get compression up. If the heads are in good shape, work with them. If they need to be worked, you really would be better off going with an aftermarket head in the long run
 
YOUNGBLOOD13 said:
Those should be oval ports, which suits your application perfectly. But more importantly, the rest of your combo needs to be matched. They would be open chamber heads which might require the pistons to have a small dome to get compression up. If the heads are in good shape, work with them. If they need to be worked, you really would be better off going with an aftermarket head in the long run
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Cool thanks for info. What do you recommend for a cam?
 
Near as I can tell, they are large ovals and open chamber, and that casting is 396/427

Cam will depend on what compression you want
 
Frankenblazer said:
Like to be able to run on pump gas.lol ,so I guess 10,1
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The answer is always roller cam. So that's really expensive

A good hydraulic cam usually is a good option without a big increase in the budget
 
Cam does nothing to change static compression ratio. Do you know what compression you are running? Probably not from the sound of it. Cam choice depends on intended use, compression, tire size, transmission/converter, gear ratio for starters. If you have all of that info, it's easy to select cam for best power. If you are looking for a driver cam, look for a relatively small cam, and aim for big torque, not horsepower. If you can afford roller, by all means do it. If not, try something like this: https://www.summitracing.com/parts/cca-k11-231-3/make/chevrolet
 
On compression, 9:1 or so is pretty usable on a bbc. You will make a lot of heat cranking past that, and it may not be worth the extra cost is you have to change pistons

I can look up some numbers here



The roller cam systems for these engines go well into the $1k plus range, FYI

https://www.edelbrock.com/performer-plus-camshaft-kit-for-big-block-chevy-396-427-454-v8-2162.html


Note they changed the heads on this one
https://www.edelbrock.com/performer-plus-camshaft-kit-for-big-block-chevy-396-427-454-v8-7162.html
 
Excellent thanks for the info. Guy I bought it off didn't know anything about it supposedly the guy he bought off died but owned a junkyard, which is probably true because everything about this k5 is from 80 to 92 except engine and trans.lol
 
Weiand makes a good intake for these as does Edelbrock. Both will go well towards making a good street engine.

If you want that 500 number you will likely have to start spending more money. But either of those will probably make 425 hp 475-500 lb/ft
 
Very good info .it had a 3500 stall speed conv ,which supposedly match the cam.which it sure felt like it,last month I noticed trans was cracked almost all the way around, so the trans shop recommend I go with a 1800 to 2000 stall speed and change my cam to match
,so that's where I'm at now
 
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