Re: Re[6]: Tech Question - 'A' Block heads

From: JT McBride (James.McBride@GDEsystems.COM)
Date: Fri Apr 04 1997 - 13:19:10 EST


>>intake manifold for the production Magnums are identical - 5.2 & 5.9l.
>flow like mad. Choker in the system is probably the TBI. Oh Jules...

Whaa... I don't understand what you're talking about. I mean the MPI
Magnum intake. I'm pretty sure they're the same 5.2l and 5.9l.

> The crate motors are 4.00" bore and a 3.58" stroke. I think
>the 5.2L are 3.91" bore and a 3.23"-3.25" stroke (can't remember).

Assuming the Magnums use small block cranks, the bore is 3.91" and the
stroke is 3.31". A mild overbore (0.040) to 3.94" and a 3.65" stroke
give 356 cid - a nice number, I think. Close enough to use the 5.9l
computer with, I'd reckon. Especially with ported intake/exhaust,
which are likely to flow about as much gas as a good 360 (at least).

The beauty of closed-loop MPI is that the computer can tweak things a
bit to get good stoichiometry. You still need a computer that's got
a good idea of the basic setup though, since they run open-loop until
the O2 sensor warms up.

Anyone know what the lift and duration of the '96-'97 stock roller cam
is - and whether 5.9l Magnums get the same cam (Grand Cherokees and Rams)?
I suspect they do, and that the RT/1 gets the .46 MP cam.

Crane's been mentioned a few times on the list. What fairly mild street
cams do they offer?

I'm going to run a compression check this weekend to see just how healthy
this engine is - oil is disappearing somewhere (no spots on the driveway).
I've been pretty good about oil changes, and I was really hoping this
would go 200K miles before I needed to rebuild/replace. 107K now.

Jim

--
Happiness is (according to Aristotle): "The exercise of vital powers
along lines of excellence in a life affording them scope."



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