96 cam or 89 cam

First off, can i use my 96 dual pattern stock cam in my 89 block with 89 lifters?

Secondly, which should i use (the 89 cam or 96 cam) to make more torque down low in my 4.6L .040 bored stroker?

I am using an 89 block (40 over)
96 head
stock 4.2 40 over pistons
hvlp oil pump
24 lb brothers racing injectors
and the do it your self MAF mod

the truck will be used as a chase truck for our race team in the desert and as a rock crawler whenever i can.

thank you for your input, cam choice is holding me up on my project...

john

frogmanjohn said:

First off, can i use my 96 dual pattern stock cam in my 89 block with 89 lifters?

Secondly, which should i use (the 89 cam or 96 cam) to make more torque down low in my 4.6L .040 bored stroker?

john

Click to expand...

Always reuse the lifters that were worn with the cam, and only in the same lifter hole and lobe of the cam. If you did not index the lifters when you removed them (1E, 1I, 2I, 2E, 3E, 3I, etc.) to put them back in the exact same lifter boss to ramp on the same lobe, then only install new lifters. The risk of swapping a lifter or running an unmatched worn lifter is cam failure.

The rebuilders rule is new lifters (cheap and easy insurance).

The 96 cam has more E/I overlap, designed into the timing to leave a higher concentration of unburned exhaust in the chamber. This reduces the combustion temperature and lowers the NOx emissions, a method of cam timing that allows elimination of the EGR in the intake (the EGR accomplishes the same thing). The later 99+ head further restricted the exhaust to improve this effect at the low engine speeds where emissions are tested.

The stock answer is the cam should best match the method of exhaust treatment to minimize NOx, i.e. match the intake you plan to use (with EGR like the 89, or without like the 96).

The power from either cam will be very similar, although the undiluted combustion charge due to the reduced overlap in the 89 cam directly relates to the better low rpm torque of the non-HO design. The 96 head and intake with the 89 cam combines the best of both stock designs (but you need to use a three-way catalytic converter to assure it will pass emissions testing).

The aftermarket cams often recommended in the performance forum do provide a benefit, with the same concern for emissions control and excessive E/I timing overlap to manage without an EGR valve or healthy cat. They also need to be combined with other improvements to exploit the benefits.

HTH?

Thank you very much for the detailed feedback, my intake manifold is off a 93 (the body is a 93 as well). so with that being said, i believe that uses a egr valve right? so i should use my 89 stock cam correct?

I do have all new lifters for an 89 block, but am planning on using my 96 stock pushrods due to using the taller 96 head, does that sound right?

john

it will not have an EGR valve. EGR was deleted by Mopar with the HO introduction. I say use the cam that was intended with the head, but I don't know squat

yup, sorry to bring this up from the dead, but just wanted to input some info for any others building the 4.7L stroker and looking at different parts..

parts used..
89 block
96 head
89 cam
4 brothers 24Lb racing injectors
93 computer
banks header
obd2 high flow cat
flowkooler water pump

And after being driven almost daily for 5 years...
She passes smog cleaner than when she was when she was new. And runs very cool. If anyone has any specific questions on this build, please don't be afraid to ask.

A little late but I'd use the earlier cam. Correction on that you do not use oversize 4.2 pistons in a stroker. You use 4.2 rods with oversize 4.0 pistons or use 4.0 rods with custom pistons or KB944/945s.

gradon said:

A little late but I'd use the earlier cam. Correction on that you do not use oversize 4.2 pistons in a stroker. You use 4.2 rods with oversize 4.0 pistons or use 4.0 rods with custom pistons or KB944/945s.

Click to expand...

I agree bud, thats is what i did and it has worked out great. I used the rods and the 80LB 4.2L Crankshaft from a 71 for the extra rotational mass since i mainly rock crawl. And used 40 over 4.OL pistons. This was an old thread of mine that i dug up and just wanted my results on the board to aid future searchers that might be debating on stuff.

Very cool info. I recently heard the non HO4.0s had better low end and I always noticed that from my 88 motor but wanted to know why. The emmisions cam overlap is very interesting.
Thanks for bringing this thread back. I'm not too interested in building a stroker (yet) but I just found out the main bearings in my mysteriously rebuilt motor are screwed though it runs like a beast. The cam journals were smooth as glass so I'd like to tear it down and see whats been monkeyed with and build a strong mild 4.0 with a newer head and all that eventualy.