Engine guys help?
Thread Starter
Instructor
Joined: Feb 2013
Posts: 112
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From: Tucson Arizona
Engine guys help?
If I get a 400 sbc motor bored to a 4.154 bore, is there a way of using pistons from a 396 bbc that has the same bore size? If so how would I go about doing that? I can't find any small block pistons with that bore.
Last edited by shua1269; Jun 19, 2013 at 04:24 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
I can't imagine a stock 400 block having enough cylinder wall thickness with bores that size.
For the 396 piston idea, the size and geometry of the wrist-pin location in the piston would need to be the same; also, the piston rod would need to fit on the 400 crank and to piston wrist-pin. Not sure who would know that info other than a place that sells those pistons and rods.
For the 396 piston idea, the size and geometry of the wrist-pin location in the piston would need to be the same; also, the piston rod would need to fit on the 400 crank and to piston wrist-pin. Not sure who would know that info other than a place that sells those pistons and rods.
Race Director
Joined: Jan 2000
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From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
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.030 over pistons are available everywhere.
No...you can't use BBC 396 ones.
JIM
No...you can't use BBC 396 ones.
JIM
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Safety Car
Joined: Mar 2007
Posts: 3,652
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From: Bridgewater nj
You can't use a BBC piston but I'm sure you'll find a piston! The machine shop has the book with stroke, rod size and bore. Thumb through it and you'll have your piston. I had a Pontiac piston in a 403 Oldsmobile that was bore .060 over. Needless to say that motor didn't last long 
Thread Starter
Instructor
Joined: Feb 2013
Posts: 112
Likes: 0
From: Tucson Arizona
Thanks for the info guys! I was calculating wrong. To get to the 4.154 bore it would be .029 over. and there are no pistons that will fit that. Guess I gotta go even at .030 over and I know there are a million pistons for the 400 .030 over.
Racer
Joined: Dec 2008
Posts: 297
Likes: 19
From: arlington TX
Hi,
Things aren't always what they seem -
When I have bought pistons (say, .030 over) from a good manufacturer (I usually used Wiseco), they actually measure about .025 over. With a 'true' .030 over-bore in your block, that gives you .005 clearance - a good stating point. A .029 over-bore and a .025 piston will give you .004 clearance, a little tight for forged pistons and a little loose for hyperutectic pistons. Measure both bore and pistons to see where you stand.
Talk to your trusted machine shop, tell them what your pistons measure out (or bring them the pistons) and they should be able to get you whatever clearance that you want.
If you don't want to do the measuring, then new .030 (.025) over pistons and a new .030 over-bore will probably work most of the time. Your gamble.
Good luck.
walt
Things aren't always what they seem -
When I have bought pistons (say, .030 over) from a good manufacturer (I usually used Wiseco), they actually measure about .025 over. With a 'true' .030 over-bore in your block, that gives you .005 clearance - a good stating point. A .029 over-bore and a .025 piston will give you .004 clearance, a little tight for forged pistons and a little loose for hyperutectic pistons. Measure both bore and pistons to see where you stand.
Talk to your trusted machine shop, tell them what your pistons measure out (or bring them the pistons) and they should be able to get you whatever clearance that you want.
If you don't want to do the measuring, then new .030 (.025) over pistons and a new .030 over-bore will probably work most of the time. Your gamble.
Good luck.
walt
Thread Starter
Instructor
Joined: Feb 2013
Posts: 112
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From: Tucson Arizona
I spoke with my machine shop and got to this point, so here's what I have so far:
sbc 400 (509 Block 2bolt main)
fresh bore(.030) and hone
flat top srp pistons
6" rods
callies stealth crank Shaft.
I the opportunity to get a new crane cam PN: CC-320A-NC for super cheap. Description from Jegz says RPM 5000-8600; Adv. Dur. 320 Int./Exh.; Valve Lift .599 Int./Exh.; Lobe Angle 108 deg.; Jegz part number 114721
I also have access to a weiand team-g single pane intake.
What Heads should I go with this set up? Should I find a different cam? Different Intake?
sbc 400 (509 Block 2bolt main)
fresh bore(.030) and hone
flat top srp pistons
6" rods
callies stealth crank Shaft.
I the opportunity to get a new crane cam PN: CC-320A-NC for super cheap. Description from Jegz says RPM 5000-8600; Adv. Dur. 320 Int./Exh.; Valve Lift .599 Int./Exh.; Lobe Angle 108 deg.; Jegz part number 114721
I also have access to a weiand team-g single pane intake.
What Heads should I go with this set up? Should I find a different cam? Different Intake?
Racer
Joined: Jan 2010
Posts: 261
Likes: 4
From: Albuquerque Resistance is not futile. It's voltage divided by current.
Take some more time to think about exactly what you want from the motor. Then pick the heads, then pick the intake, then pick the cam to
match those components and your desires. (For the engine! Get your minds out of the gutter!
) Your shortblock sounds good, .030 over 6" rod 400 will make great power, and be very streetable, with the right components!
BTW, back in the early 80's, a 509 was a choice block to build a sprint car motor out of. Splayed 4 bolt caps, Carillo rods, cant remember what kind of crank, Brodix heads, proper machine work.
Also, I dont think we'd bat an eye on 60 over, especially for a streeter. Cant remember for sure, could be wrong.
Good luck on the build, GA
Racer
Joined: Dec 2008
Posts: 297
Likes: 19
From: arlington TX
Bottom line - you can drive any cam you want on the street, but some will be more fun than others!
Even if the cam you have is REALLY cheap - $50.00 or less - it may not be what you expect on the street. No vacuum for headlights, brakes, etc. And not much performance until you really get it wound up. This motor is too small to be able to 'cover up' the low rpm weakness like a bigger motor would. Lots of clutch slip (or a loose converter - 4000 rpm or better) will be needed to get going from a stop.
Nice cam for the strip or for comparing cam specs (Mine is bigger than yours) while bench racing, but for street fun, I'd dial back the specs, especially duration and have more fun.
Just for comparison, my race cam was 305 adv duration (285 @ .050) and 570 lift in a 362 small block. It had no vacuum and would hardly idle below 1500. But with a 5000 rpm stall converter and 456 gears, it would run great at the strip.
But do what you want (that's what is called "experience"). You can always change cams later.
Good luck.
walt
Even if the cam you have is REALLY cheap - $50.00 or less - it may not be what you expect on the street. No vacuum for headlights, brakes, etc. And not much performance until you really get it wound up. This motor is too small to be able to 'cover up' the low rpm weakness like a bigger motor would. Lots of clutch slip (or a loose converter - 4000 rpm or better) will be needed to get going from a stop.
Nice cam for the strip or for comparing cam specs (Mine is bigger than yours) while bench racing, but for street fun, I'd dial back the specs, especially duration and have more fun.
Just for comparison, my race cam was 305 adv duration (285 @ .050) and 570 lift in a 362 small block. It had no vacuum and would hardly idle below 1500. But with a 5000 rpm stall converter and 456 gears, it would run great at the strip.
But do what you want (that's what is called "experience"). You can always change cams later.
Good luck.
walt
Thread Starter
Instructor
Joined: Feb 2013
Posts: 112
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From: Tucson Arizona
Thanks guys. There is so much reading out there for different applications. I am going to talk to my machine shop and the Crane cam reps to get a better idea as to what would work best for my application. I now just need to build a fun motor that will spank this punk *** kid with subaru STI that has a big mouth. =)
Burning Brakes
Joined: Sep 2012
Posts: 818
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From: coon rapids mn
buy the cam last after you know you static compression ratio.check competition products for good head prices.consider some AFR 195 heads ,or some dart 215 heads.consider a hydraulic roller cam ,it will make lots of power every where.