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Discussion Starter #1
Got my 454 short block ready for assembly. Need help picking a cam. Going to bite the bullet and spend the money on a hydraulic roller setup mainly for longevity's sake. Here's what I have:

Tall deck 427 block .040 over
454 crank
Flat top pistons
702 closed chamber heads with stock valves
Compression ratio calcs right at 9.5:1

This is going in a 4 wheel drive pickup that will tow very heavy on occasion and get hotrodded the rest of the time. Going to be geared quite high (3.54 gears, .77:1 overdrive manual, 33" tires) but will run between 70 and 85 MPH on the highway - 2000 to 2400 RPM. Obviously I need emphasis on low end torque due to the gearing and stock heads.

Any suggestions on a roller cam? Brand and grind?
 

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At 60 mph you will be at 1600 -1700 RPM’s so you may want to limit OD to 70 or 80 as you say. A short duration cam 215 or less with a converter to complement heavy towing. Big diameter tires cut down on torque multiplication. I’ve done highway towing w/ 31” tires & 3.73 gears and ride & power was ok.
 

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Your piston choice made note of the fact you've got the .400" taller deck block in play here, correct??
A standard 454 piston is not going to be right, it will be nearly 7/16" short of TDC unless you went to longer rods or taller compression height pistons...or both together added up.
 

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Discussion Starter #7
Your piston choice made note of the fact you've got the .400" taller deck block in play here, correct??
A standard 454 piston is not going to be right, it will be nearly 7/16" short of TDC unless you went to longer rods or taller compression height pistons...or both together added up.
Couldn't find a piston with the correct compression height so I am using the 427 tall deck pistons and running a Cometic .140" head gasket. Protrusion will be right at .105".
 

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whqt are you using for fuel management and exhaust?
Probably headers and dual 2 1/2" or 3" pipes.

Carb will be a 750 Eddy unless I get ambitious enough to tune a Holley for it.

Either that or a 600 Eddy if it would be better suited since it won't see much over 4K RPM.
 

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Couldn't find a piston with the correct compression height so I am using the 427 tall deck pistons and running a Cometic .140" head gasket. Protrusion will be right at .105".
Well, good luck with that and getting intake and distributor to fit, seal, and connect.
Both are going to need corrections made.

Don't forget it changes pushrod length also.

Normally, guys would just use a longer aftermarket connecting rod to use a tall deck block for performance....along with building a bigger stroker rather than just a common 454 using a bastardized block.

Seems like a disaster of a build, that you've got planned, really.

What was the point of using a tall deck block to build just a common 454 cube engine the hard way?
 

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Well, good luck with that and getting intake and distributor to fit, seal, and connect.
Both are going to need corrections made.

Don't forget it changes pushrod length also.

Normally, guys would just use a longer aftermarket connecting rod to use a tall deck block for performance....along with building a bigger stroker rather than just a common 454 using a bastardized block.

Seems like a disaster of a build, that you've got planned, really.

What was the point of using a tall deck block to build just a common 454 cube engine the hard way?

Had a pretty fresh 427 tall deck with a burned valve. Had a near new 454 boat engine with a broken block. Got a set of 702 heads with low miles. Mix it all together and you get a bastardized 454 tall deck with the right compression ratio for nothing more than the cost of a rebuild kit.

Yes, I would love to make it a 496, but that takes more money. Yes, I could have found a cheap 454 block, but that still takes money and it would likely need bored which would again cost more money. Money isn't really an issue, but I like trying to get by cheap. Ideal by any means? Not at all.

If somone knows of a set of .040 over pistons with the correct compression height though, I would be all ears.
 

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If somone knows of a set of .040 over pistons with the correct compression height though, I would be all ears.
Yeah, I don't believe one even exists for this combination, every build I know of using a TD block uses longer rods in it too, and pistons are available accordingly for that....and I don't believe any of those will be cast or Hyper, strictly forged.
I bet the only way you would get a piston correct for the parts you have is to buy custom made forged....nobody does custom compression height cast or hyper pistons...no market for them.

I think you would be smarter to investigate cutting the existing piston top down to fit....I've taken .100" off the top of dished cast 400 pistons to use them with longer rods, turning them into flat tops, with no issues. I would expect the stock TD 4 ring pistons to be well overbuilt enough that cutting them down to fit will be a serious possibility you should look into.

Otherwise, you are really going to fight with intake and distributor fit.

I take it you are planning to make some custom intake spacer plates?
Any available short to tall deck adapter plates will be too thin due to that whopper .140" thick head gasket.
Distributor will need to be an adjustable collar model, or a stock distributor with the housing re-machined to take a adjustable height collar.
 

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Doesn't get much cheaper than that to come up with a better solution. Net difference in build cost is only about $100, since you no longer need $300 worth of head gaskets and can do it with $50 worth of head gaskets.

Does leave piston-to-deck at .040" down though at TDC, with the parts stack coming to 10.160" in the nominal 10.200" block.
Mr Gasket soes have a .018" thick steel shim gasket that would help. #1131G, $24 ea @ Speedway Motors.
At best quench is .058" with this set-up.

Another piston option, 1.645" compression height to leave piston just .020" down on undecked tall block...

CHEVROLET Silvolite Pistons 3458H-040 Silv-O-Lite Hypereutectic Pistons | Summit Racing

It is a .133 tall solid dome, you'd have to machine the dome off some to get to a lower compression ratio but dome is solid and easily milled or lathe turned off to any height you desire.
With the .018" thick head gasket you would preserve .038" quench, not need funky thick expensive head gaskets, eliminate the 10 lb 4 ring pistons, eliminate custom intake and distributor fit-up issues beyond normal tall deck mods....
seems like a smart win to me.

Nearly the same, at 1.640" height and a .100" tall solid dome to trim off as needed...makes quench clearance .043" with the .018" thick gasket.
CHEVROLET Speed Pro H426CP 40 Speed-Pro Hypereutectic Pistons | Summit Racing

THIS ^^^ seems like the only real alternative with the ProComp rods, since they are bushed you need a floating pin piston....raises cost another $50 but you don't have to pay for piston press off and on the stock rods.

To me, a simple mill or lathe cut on the dome versus all the other crap you have to do to cobble it up with the 4 ring clunker makes these solutions the smarter way to go
 

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Discussion Starter #17
Doesn't get much cheaper than that to come up with a better solution. Net difference in build cost is only about $100, since you no longer need $300 worth of head gaskets and can do it with $50 worth of head gaskets.

Does leave piston-to-deck at .040" down though at TDC, with the parts stack coming to 10.160" in the nominal 10.200" block.
Mr Gasket soes have a .018" thick steel shim gasket that would help. #1131G, $24 ea @ Speedway Motors.
At best quench is .058" with this set-up.

Another piston option, 1.645" compression height to leave piston just .020" down on undecked tall block...

CHEVROLET Silvolite Pistons 3458H-040 Silv-O-Lite Hypereutectic Pistons | Summit Racing

It is a .133 tall solid dome, you'd have to machine the dome off some to get to a lower compression ratio but dome is solid and easily milled or lathe turned off to any height you desire.
With the .018" thick head gasket you would preserve .038" quench, not need funky thick expensive head gaskets, eliminate the 10 lb 4 ring pistons, eliminate custom intake and distributor fit-up issues beyond normal tall deck mods....
seems like a smart win to me.

Nearly the same, at 1.640" height and a .100" tall solid dome to trim off as needed...makes quench clearance .043" with the .018" thick gasket.
CHEVROLET Speed Pro H426CP 40 Speed-Pro Hypereutectic Pistons | Summit Racing

THIS ^^^ seems like the only real alternative with the ProComp rods, since they are bushed you need a floating pin piston....raises cost another $50 but you don't have to pay for piston press off and on the stock rods.

To me, a simple mill or lathe cut on the dome versus all the other crap you have to do to cobble it up with the 4 ring clunker makes these solutions the smarter way to go
You guys are making some good sense. Thank you for the ideas. I do have a lathe in the shop - if I just turn the dome off would I have to worry about the top of the piston being too thin?
 

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You guys are making some good sense. Thank you for the ideas. I do have a lathe in the shop - if I just turn the dome off would I have to worry about the top of the piston being too thin?
Cast and hypers are almost always solid dome, only a very high domed hyper might be hollow, and most forged with a dome under .300" tall is solid, unless advertised as a hollow dome "lightweight" piston.

Everything posted related to your build is a solid dome, you can cut it down to a flat top or even a small dish if you desire....just do some thickness probing underside of the dome first to be sure how much room you have if you are going to carve a dish.
As a general rule, minimum top thickness across a piston is .200", .220" to be safe, with the exception of small areas at the bottom or side of a valve relief cut....down to .150 thick in a small area is acceptable.
 
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