rebuilding lowerend end of 6.5 is there anything perf i could do
 

okay so here is the scoop i have a 1988 suburban that is rust free i will be using to tow my mud truck the stock 350 with 350000 miles is tired and i need something with a little more pep i have a buddy that has a 6.5 that the lower end went out as soon as he heard the knock he shut it off he is going to sell me the motor wiring harness and computer for 300 bucks a crank kit is 270 is there anything else i will need other than the wiring harness and computer to put the 6.5 in i know i need a sending unit and diesel tank btw this is coming out of a 95 truck would a 400 turbo work to tow or should i see about getting a 4l80 and wiring for it because of overdrive every response is appreciated btw i am a newb at this forum

Well, for starters you will also need the throttle pedal as all 6.5's after 93 are "drive by wire". IE: no throttle cable, all electronic. The throttle pedal on the 6.5 is just a big potentiometer that sends a signal to the PCM.

Also off the top of my head:

lift pump
Trans output speed sensor, DRAC/Vssb. The PCM needs these to run the engine properly. Probably easier just to swap in the 4L80E, then you'll need to find a way to get the shift selector in there and working with you old column. Then you're going to have to probably get custom driveshafts...
Probably the rest of the dash wiring (for the drac, etc)
If you elect to swap the trans that's probably going to mean you need the dash cluster
Custom bent exhaust
Dual batteries and wiring
Glow circuit (can be done with just a momentary switch on the dash)
Diesel sized rad, plumbing and associated surge tank, etc.
Hydro boost brake system (all of it, diesels don't make vacuum to run your vacuum brakes)

What I would do is just park the two side by side and swap the entire drivetrain over to the 88.

You can avoid all of this stuff if you swap over to a DB2 pump instead of the 95's DB4. The DB2 is mechanical (ie: no computer). It will work with your trans and cable throttle. You also avoid the wiring and trans sensor issues. No DRAC/VSSb either. Get the pump, lines and throttle cable off a donor. I'd probably grab the pedal also. A DB2 should also work with your cruise (if you have it).

Now for the bad news;

If the crank went, it probably took out the main webs in the block.

Make sure you get that thing open and inspect the block. Pay VERY close attention to the main cap bolt holes and the cap registers. These crack under normal use, a crank failure beats the crap out of them.

A stock 6.5 isn't much more than a 350 in the power department. Bit more torque, but not a lot to speak of. I've had a tbi 350 in an 89 eclb K1500 and a 98 eclb K2500 at the same time and there was virtually no difference driving either one (powerwise that is). It took a couple thousand in parts before the 6.5 felt appreciably stronger than the 350. It's not that the 6.5 is TOTAL crap, it's that the 350 is just a great engine. The 6.5 is only a 395 and you've already got a 350. The difference between the two is the turbo and the slightly higher energy potential in the diesel fuel itself.

If it were my truck?

I wouldn't even try to swap over the electronic DB4, I'd go DB2.

I'm pretty sure you're going to be cursing that 6.5 up and down by the time you get it running, and then every couple months once you start working it.

I'd probably skip the whole 6.5 idea and build a 383 stroker.

If I wanted flat out towing strength I'd slip in a 454 and be done with it. You'd just have to pay up at the pumps....

it is only going to make one or two trips a year towing a total of maybe 8 hours a year i have had 383s and i didnt like mine and i dont want a gas sucking pig of a 454 when i am just driving around town. i have thought about it a lot and want to do the swap. my buddy has had 6.5s all his life as his dad has had one since they came out so they can work on them pretty well this is his first one to have something like this happen. it just had brand new heads put on the motor and now it will have a new crank as long as eveything in the lower end is good for new parts and i will check before i decide to do the swap and then it will be good for another 300,000

Your call bro.

I think you're going to be disappointed once you get the oil pan off though...,


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[QUOTE=great white;866421]If the crank went, it probably took out the main webs in the block.

Make sure you get that thing open and inspect the block. Pay VERY close attention to the main cap bolt holes and the cap registers. These crack under normal use, a crank failure beats the crap out of them.

I wouldn't even try to swap over the electronic DB4, I'd go DB2.[QUOTE]

x2 usually if the crank went the block and/or main caps are junk, however, if not, replace the crank and make sure you put a fluidampr on it.

x2 with the mech. IP. you dont want the electronic ip. waste of time with the stupid PMD and all the APPS if your going to put it in a truck that didnt have it.

my thing is how much better mpg wise would a 6.5 be because a sbc will get about 8 towing i usually get 12 empty

Depends on weight and frontal area on your load but my 98 gets around 10-12 towing our 35 foot long, 9 foot high, 8000lb travel trailer.

Of course, it only gets around 14 mpg empty anyways (4:10's)....

Pic in sig line.


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i get about 18-20 with my 95 6.5 (4.10) and about the same with my other 95 (3.73) but smaller tank

None of mine ever got the same fuel economy. I have had 94 cclb 4x4(4.10) get 19.5 and a 95 ecsb 2wd (3.73) get 14. You can figure you will do 14-20 empty. They are all over the place.