454 stock block bore

[406jeep]

What is considered the safe max overbore on a 454 stock block?

[85Iroc]

Un-filled??

[Mike Stark]

Depends on the casting. Most all of them will go +60. Plenty of them will go +100 and some can even go +125. I would look at filling anything going over +60 though.

[406jeep]

I am thinking of a motor for my 56 Chev PU. It would be a street/strip affair so no fill. Would worked over oval ports work very well for a 6000 rpm 454? If so what #s and what valve sizes would be best to use? I am thinking of a solid cam, Eagle rods, 9 to 1 compression. I don't know squat about big blocks, just would like something that would be somewhat streetable and still run some descent times in the 8th mile. Maybe 600 horse without nitrous and 850 with. Is this doable?

[67RS502]

Oval-ports with 2.19/1.88 and some bowl work will pull 6500-7000 on a 454 no prob.
Keep the comp under 10:1. Big solid cam a good single plane and 600HP is doable.
An HP950/1000, and 2" headers would be good.
Good ovalports will support 650+hp.
For ref. my 502 made 625 @ 6200, and thats with a hyd. roller

[chris]

I have just a general quesiton on a bbc 454 buildup.

2000 vortec 454
edlebrock vortec cylinder heads(performer style w/smaller combustion chamber)

comp cams HR w/1.7 full roller rockers
Duration at .050: 245
Intake Valve Lift: 0.612
Exhaust Valve Lift: 0.612
Lobe Seperation: 110°

edelbrock victor intake w/ commander 950 tbi setup
2" mid length headers w/ mandrel 3" ex & flowmasters

this is in a 4000lb caprice w/ a custom art carr 700r4 w/transbrake and 4500 stall on the brake. 3800 on foot brake & reverse manual valve body. with a unitrac(burnt posi clutches) 3.42 gear and launching at idle it ran a 13.4@108 on 1 drag radial.

Now the question: this engine will not pull past 4800 rpm, from 3000 to 4500 it is an animal, by 4800 it's about done and just kinda rev's to 5500. you shift and wham it lays you back in the plush seats again. I have talked with comp cams and they seem to think that it is an induction or exhaust problem. we errored on the small side for the headers following the bigger is not better process but is that BS in this case? Could also be the TBI setup holding it back, but that bad? I know there is a high 11 in this car with some good traction and a better gear/posi....please help.

here mustang mustang....

[Mike Stark]

Could be the valve springs. HR's are have REAL heavy lifters in a BBC. I would try Comps beehive springs for some more RPM. The headers are fine. A 2" tube is plenty for that car.

[hsutton]

A friend of mine did a 450 horse 502 and added a bigger hydraulic roller cam in the motor. He had the same problem with tons of torque but would only run low 12s @ about 108. Even uncapped it was a turd. He took the heads off it a they found almost all the inner valve springs had broken. He changed the springs but this engine just doesn't want to run hard. I'm puzzled by your "Vortec" heads, exactly what kind of heads are you trying to describe? Are they like the tall port 496 big block head similar to the LS-1 one small block, or just the run of the mill square port gen 5 one? What is the casting number?

[CNC BLOCKS NORTHEAST]

This is a pic of a 454 block that has come in for some work as it only has about 3200 miles on it since the rebuild and it was making some lower end noises. We line honed it and squared and decked it flat and bored it and we blued up the 2 center cylinders installed the gasket and torque plate and went in for 6 strokes on each cylinder as you can see the results and look at the piston as it has blowby right to the oil controll rings as we could measure .003 distortion on the cylinders.



The other side.



Comments are welcome