RE: Magnum 360 Short Block ?

From: Holloway,Frank T (Frank.T.Holloway@KP.ORG)
Date: Sat Oct 30 1999 - 18:58:42 EDT


GS,

I don't know much about the short blocks that Mopar Performance sells and I
don't think they know much about them either. The Magnums don't have the
same balance factor as the early A-engines. The rods are the same but the
cranks are different (balance factor). The Magnum pistons are a heck of a
lot lighter than the A-engine equivalents. Vibration dampers and flex-plate
or flywheels are different. One would need to find out what crank they are
using. Timing chain cover and cam would need to be changed (Magnums don't
need the accessory drive for the fuel pump). The cam would be way to much
for computer controlled vehicles (lift is OK, but the duration is way too
much). LSA on the cam is way too small (108 degrees) and needs to be at
least 112 degrees. On short block P/N P4876906, they call the compression
height of 1.580, even if you deck the block .020 inch, that figure would put
the pistons .080 down in the bores (not good). I have no idea how they could
possibly get the CR's they are claiming. Even P/N P9876913 would still have
the pistons down in the bores. I really think these engines are replacements
for early A-engines and MP they said that they were in the process of
changing the piston combinations. The heads are the same for the 318 and 360
(no difference). IMHO, I think they are a good deal for early engines, but I
would wait until MP gets their act together before purchasing one as a
replacement short block for Magnum vehicles. Magnum cores can be had at
reasonable prices (I just got 10 core engines for the Landy's). You can get
a replacement short block assembly with your choice of pistons, rings, cam,
and bearings from top notch rebuilders for about the same price.

        Frank

> -----Original Message-----
> From: GS- [SMTP:GSWillhite@ualr.edu]
> Sent: Thursday, October 28, 1999 9:15 AM
> To: dakota-truck@buffnet.net
> Subject: DML: Magnum 360 Short Block ?
>
> Several months ago we talked about the 360/300 & 360/380
> Magnum crate motor and how difficult it is to adapt to
> our Daks. I was wondering if the 360 short blocks would
> be easier? Say take the one with the lower CR like 9.5:1
> and stick my 318 heads on it (I think swede said 318/360
> heads are the same). I know the cam has much higher lift.
>
> I guess the real problem would be would it work with the
> stock or MP computer. Probably would not be talkin' any
> type of gas mileage here, but thats not what I'm after.
>
> Oh yeah, I think the 360 has a different flywheel and is
> externally balanced. Maybe do a slight mod to the stock
> manifold (I know Frank) to help take advantage of the
> higher breathing cam and install a crank position sensor,
> I don't think the Mag short block has one?. For the price,
> $1200-1500 for the short block, you can't beat it.
>
> GS -
>
> 98 5.2L 5spd



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