I Need New GM Crate Motor Info F/ "M" Series 350

[Dave1]

I have a 1986 GMC K-20 3/4 Ton Pick Up with an "M" series carbrueted 350 engine. After 200K miles am having some engine trouble and rather than spend money on my old engine am thinking I would rather replace it with a brand new GM crate motor.

From what I have been told from several GM suppliers the exact heavy duty "M" series 350 has been discontinued at GM and is no longer available. Does anyone know what that part number was? Maybe I can find one sitting in one of the parts supplier's warehouse somewhere.

If that engine cannot be found, what is a suitable bolt in new crate motor replacement engine?

Thanks, Dave
[email protected]

 

[u2slow]

I would suggest an '87-95 style TBI 350 for the same GVW application. I believe the high GVW engines have different alloy and/or extra hardened valve seats.

You would need to swap on a 4V intake from 87-88 passenger car... or modify 4 bolt holes on your existing intake. The 87-95 heads use center-bolt valve covers and 2 intake bolts on each head are at a different angle.

 

[akbound]

Not exact, but would work.....

This is from GM: http://www.gmpartsdirect.com/results.cfm?singlepart=1&partnumber=10067353

This would be alot cheaper than the previous suggestion and can be obtained from your local GM dealer (you may experience a mark-up, however)






GM PART # 10067353
CATEGORY: Eng Asm-(must provide commercial shipping address)
PACK QTY: 1
CORE CHARGE: $50.00
GM LIST: $2,608.54
OUR PRICE: $1,329.00DESCRIPTION: New 350 ENG LM1 Four Bolt Main $1329.001969-85 GM Vehicles 350 Engine

This is for 85 and older vehicles and has the perimeter bolt valve covers and a two piece rear-main seal. All brand new components NEW four bolt main block. Not Remanufactured / Not Rebuilt! An all new 350 Chevy engine backed by the GM warranty. This engine can also be used in 1986 model pick-ups in combination with a new flexplate (flywheel) must also be changed. Use flexplate #471598(2 piece rear main seal) when used on 1986 and newer. (note: shipping qouted is to a business address, residential deliver will be higher)

 

[u2slow]

I agree... the 85-older flexplate should be cheaper/easier to source than the intake I suggested. (Hehe... and is a whopping ~$500 cheaper than the 87-95 engine )

GM PART # 12568758
CATEGORY: All
PACK QTY: 1CORE CHARGE: $100.00
GM LIST: $3,166.32
OUR PRICE: $1,896.00http://www.gmpartsdirect.com/result...ber=12568758&singlepart=1&partnumber=12568758DESCRIPTION: ENGTL05GW

However, neither seems to list the GVW application they are intended for

 

[Dave1]

The GM part number suggested #10067353, according to the manual descriptions, is for a light duty application thru 1985 and yes it is cheaper by several hundred dollars.

The only current part number listed for any 1986 GMC 350 pick up truck engine is #12568759 (I think, as I am working from memory). I found several of these new GM crate motors around but they are quick to tell you this is NOT an exact replacement for my "M" series engine. Not sure if any modifications are required to make this engine work in my truck or not.

A shop mechanic reccomended a Jasper rebuilt engine today, said their nationwide warranty is better than any and even covers labor to repair or replace in the event of a failure. Says engines are dyno tested and are perfect or they don't leave the factory. It sounds impressive but I haven't looked to see if they make an exact replacement or not. I cannot believe a rebuilt anything would be better than brand new GM engine.

Any opinions, information, or feedback???

BTW, when this is over I will likely have my "M" series 4 bolt main 350 for sale. From what I am told this is the one all the racers and HP people want.

Thanks, Dave
[email protected]