02-16-2009 08:05 AM #1
429/460 build up
I am gettin ready to build a new engine for my truck.. I have 429 cj code r heads.. I have 429 and 460 complete motors,, need to know what cam and pistons to run to get the most from the heads,, I drive the truck daily use for towing, hauling, have 373 rear end c 6 trans with gearvendor overdrive..the 460 block I am running now is ok but the heads are not performing right .running a wyn intake mathed to work on Cj heads any sugestions??? Jerry
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IMO the CJ heads are too big for torq purposes. I would use early base 429 heads
|A Ranchero is NOT an El Camino|
A 4.11 rear gear with that gear vendor would be nice also...
It sounds like a low rpm build,bolt in a 4.5 stroke crank and those heads get alot smaller.
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Don't get carried away with high CR or valve duration. Trucks don't like either, you don't want to be running one gear down to keep a hi-po engine happy!
Agree with R Pope, keep the compression low so you won't have to use a long cam to bleed off compression to prevent detonation. Here's what I would do:
I'd use the 460 block, D3VE heads and Keith Black KB206 pistons. The stack with these parts and stock rods will be 10.302". Depending on the year of the block, it will be either 10.300" (early block) or 10.320" (later block) block deck height. Have the block decks cut to 10.300" if it's the later block. What we're shooting for here is a zero piston deck height or close to it with the 10.302" stack (crank radius of 1.925", rod length of 6.605" and piston compression height of 1.772" = 10.302"). The pistons are 15cc dish and will generate an 8.8:1 static compression ratio with the 97cc D3VE heads. You should be able to find a good set of these heads locally. Put a 5-angle valve job on them and a very light skim off the surface to make sure they are flat and call it good. Save the CJ heads for a hot rod build, the chambers are too small for a pump gas motor used for towing and hauling. You won't be able to find a set of pistons to work with them to bring the static c.r. low enough to work well on pump gas without detonating. Well, you could, with a long cam, but that would defeat the purpose of a tow/haul motor like Pope said. The KB pistons have a D-cup design and a nice flat plateau that will work well to generate good squish to operate on 87 octane swill. With the piston compression height close to zero, use a gasket such as this 0.041" Fel-Pro...
Use a high-rise dual-plane intake manifold such as a Performer RPM and the carburetor of your choice. Something in the 600-650 range should work nicely, although if you want to make max power with it, use an 850 vacuum secondary carb. A good set of long-tube, equal-length headers will go a long way toward freeing up horsepower in the motor.
Call up your favorite cam grinder and tell them you want a cam with an intake closing point of around 20-25 degrees after bottom dead center @ 0.050" tappet lift. This will optimize the dynamic compression ratio with the 8.8:1 static compression ratio.
Have the cam grinder send you an adjustable pushrod so you can determine the correct length pushrods to order. The D3VE's have a non-adjustable valvetrain.
Last edited by techinspector1; 02-16-2009 at 02:50 PM.
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There are several things that you can do to improve performance with your current 460. These engines, from about 1973 and up, have a dismal 7.8:1 compression ratio; the exhaust ports flow miserably; the distributor does not have so much as a hint of an agressive advance curve; the pistons are way below deck at TDC. Fix these things and the engine comes alive. But, rebuild for your specific application/needs and address these mentioned traits as well, and you will out pull Ford Powerstroke Diesels while going uphill with a trailer.
The specific combo you need depends on a lot of details; you have basically been pointed in the general direction thus far...
429/460 Engine Fanatic