I need some smart BBC guys to help set me straight. I am planning on building a 454 for my 66 Chevelle. My goal is 400 to 500 hp. I have never done a BBC build up, but this is what I have. 1974 2 bolt tonowanda block with 781 heads. I have owned this motor for 15 years and was in my pickup. Stamped for a chevelle, was not original for my truck. Anyway, the engine builder (came highly recommended by several friends) said I will be fine with the stock rods and crank at this power level. I do not plan to race the car, I want driveability and light the tires up once in a while. I plan to use the original style intake and everything I read said using a rectangular port manifold with oval port heads will work as long as I use rec port gaskets. I know there are a million different opinions, but I only want to do this once, and before we get too far, I would like some more info. The block has been tanked and rough bored thus far and will be bored 30 over. Thanks in advance for your help!
questioning engine builder
1welder
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I need some smart BBC guys to help set me straight. I am planning on building a 454 for my 66 Chevelle. My goal is 400 to 500 hp. I have never done a BBC build up, but this is what I have. 1974 2 bolt tonowanda block with 781 heads. I have owned this motor for 15 years and was in my pickup. Stamped for a chevelle, was not original for my truck. Anyway, the engine builder (came highly recommended by several friends) said I will be fine with the stock rods and crank at this power level. I do not plan to race the car, I want driveability and light the tires up once in a while. I plan to use the original style intake and everything I read said using a rectangular port manifold with oval port heads will work as long as I use rec port gaskets. I know there are a million different opinions, but I only want to do this once, and before we get too far, I would like some more info. The block has been tanked and rough bored thus far and will be bored 30 over. Thanks in advance for your help!
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12,324 Posts
Personally, I like to be conservative. What are the bolts in the rods? 3/8" will be good to 500 hp with good bolts and resizing. 7/16 would be better but not needed. I have run over 600 hp with 7/16 rod chevy rods. My dad and his friends pushed to about 700 years before. For the crank, a cast crank is fine for 500 with a good balance job and magnaflux check. I built a 408 with 7/16 rods and a cast crank and it made 500 hp at 6800 rpm. Forged chevy cranks I have run to 800 hp.
not sure what your question is, but stock stuff is good for what you want to do, engine might have thumb rods, but doesnt really matter
why use a ret port intake, get one to match the heads
good machine work, good assemb. and parts matched to everything, your good to go
why use a ret port intake, get one to match the heads
good machine work, good assemb. and parts matched to everything, your good to go
stock crank and rods are more than adequate for a 400-500 HP 454
Thanks for putting my mind at ease. I still think I might go with aftermarket rods, but may upgrade to a Scat balanced assembly. Or do you think it would be fine to use better rods and re-use the cast crank and get everything balanced? I have been looking for rec port heads to match the intake I plan to use, but have not found anything good locally, but again, from what I have read, my idea should work. Anyone have any experience with doing that?
Your fine using the sqaure port intake, just as you mentioned use the gaskets to match the intake to get a good seal.
Adding good rod bolts is about the only upgrade you should need to the bottom end as long as everything checks out correctly during the build.
Adding good rod bolts is about the only upgrade you should need to the bottom end as long as everything checks out correctly during the build.
Your rods are totally fine, but after the cost of reconditioning them with good ARP bolts, a set of scat rods is not much more at all....I would personally use the scat rods, stock crank and have it balanced. For your intentions this will work just fine.
I have 2 sets of the rods you need in stock, can help you out on the $ if your in need. Shoot me a PM.
http://www.summitracing.com/parts/SCA-310212764/
I have 2 sets of the rods you need in stock, can help you out on the $ if your in need. Shoot me a PM.
http://www.summitracing.com/parts/SCA-310212764/
Going to be to small for the range your looking at...List out your complete combo.
Your building something very similar to what we have as a recipie build, you can use this as a base line:
454
KB207 Pistons = 10:1 compression
Stock 781 Heads
Performer Dual Plane intake
QuickFuel 780cfm street carb
230/230 @50 .512/.512 lift on a 112LSA
465HP+/505TQ+
This is a great street build that puts out all around good power. You will need a similar cam to accomplish your goals. A Howards #120051-10 would be a great cam...put on a 112LSA for street use..
Your building something very similar to what we have as a recipie build, you can use this as a base line:
454
KB207 Pistons = 10:1 compression
Stock 781 Heads
Performer Dual Plane intake
QuickFuel 780cfm street carb
230/230 @50 .512/.512 lift on a 112LSA
465HP+/505TQ+
This is a great street build that puts out all around good power. You will need a similar cam to accomplish your goals. A Howards #120051-10 would be a great cam...put on a 112LSA for street use..
Don't sweat the intake, many guys have run the rect port intake on O port heads. You'd really be better off with an O port Performer RPM AG though. The block crank, rods and heads are great for what you want. Pick out a Lunati cam about 276-280, one of the VooDoo line.
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227 Posts
I just had a small block rebuilt (400). And faced some of the same questions you have. In hind sight I would have bought a complete assembly instead of mixing and matching parts. This is of course you have absolute faith in the engine builder. I know that's not much to go on, but that was my experience. I second the idea of why not do a 496? DM
Back with more questions after a lot of bar stool bench racing. Talked with my engine guy this morning about upgrading the crank, and he said at that point, build a stroker, so here is what I am planning:
454 block bored 30 over
scat kit 1-91360 from flatlander racing, 9.0-1 compression with 118cc heads
Heads are 781 castings (should be 118cc), unsure of valve size right now
Using original aluminum intake for the L-78 (want the original look)
Comp Cam with 230/230 duration and 512/512 lift
Studded main caps
Holley 4150 770cfm
This should in theory make a nice 489 right?
Also, I have never built a stroker, but I want something that runs smooth, not idle at 2500rpm and be reliable.
I have not bought anything yet, but the stroker kit lists at 1172, and my engine guy will be balancing it.
Thoughts?
454 block bored 30 over
scat kit 1-91360 from flatlander racing, 9.0-1 compression with 118cc heads
Heads are 781 castings (should be 118cc), unsure of valve size right now
Using original aluminum intake for the L-78 (want the original look)
Comp Cam with 230/230 duration and 512/512 lift
Studded main caps
Holley 4150 770cfm
This should in theory make a nice 489 right?
Also, I have never built a stroker, but I want something that runs smooth, not idle at 2500rpm and be reliable.
I have not bought anything yet, but the stroker kit lists at 1172, and my engine guy will be balancing it.
Thoughts?
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12,324 Posts
I think it sounds good for what you are doing. I would go with 2.19/1.88 valves in the heads.
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