Hi, I have a 1983 250 in a GMC truck. I want to keep it a inline 6.
I was going to spend about $2000 on the engine until I spotted this thread:

https://www.inliners.org/ubbthreads/ubbthreads.php?ubb=showflat&Number=24366&fpart=1

Now I think spending any money on performance improvements on the 250 is not cost effective.
The 4200 makes more HP stock and gets better gas mileage.

@ efi-diy Do you think your 4200 made more HP than stock with a locked exhaust cam?

We have a Trailblazer and a 5 cylinder (aint full-grown yet) Colorado, even the 3.5 Colorado w/automatic (light 2-door truck) will get second gear rubber with 265/75 x 15 tires). In most reviews of Colorados the authors complain of no power--they have only driven the 3800# four door pigs powered by the 3.5-3.7 engines. Consumer Report tested a bunch of 4-door little trucks and their tests indicated the 4-door auto 4.7L V8 Dakota was a tenth of a second faster than the 3.5L Colorado (but a mph slower)in the quarter, and they say the Colorado lacks power-then what is the Dakota (i say chopped liver). The Trailblazer is heavy at about 4800# and somewhat slow off the line with 3.42 gears, but will wail when rolling. These engines are VERY stout in stock form (the 3.5 makes 220 NET hp - same as as a powerpack '57 chevy made in GROSS hp), compare the 291 hp Trailblazer to a 303 hp 5.3 V8 - not too shabby with only on 3/4 the cylinders and about 70 less cubes. In drive both these 4 inch stroke engines will (with wide open throttles) shift at 6000 rpm. Both my vehicles only get 22 mpg with their overdrives on the highway - so let us not get carried away with the economy claims.
DYI can tell you all about converting the computer to your truck. If you dont belong to "period correctness" thinking there is no reason other than the understandable $$ not to use the 4200 over a 250.

Just something from a friend that rented a Colorado 5 cyl.

I asked about it & he said it was very slow & weak,he thought the Colorado had a small 4 cyl ,until he poped the hood.LOL

I have not driven one first hand though.

MBHD

Well the first thing to get would be a oil pan and a flywheel. The rest should be easier at wreckers or dealer.
The truck would still be a 6 cyl manual 4sp.

We bought a Trailblazer complete from a salvage auction.

It is slated for a 1950 GMC 5 window (1/2 ton).

We have left it in the trailblazer for now as it won't "loose" any parts off the drivetrain that way.

I'm scheming on puting the whole fuel system in the Jimmy (tank and all) with perhaps a turbo later.

We (pops and I) plan to keep the trans that came with it (no adapters required) and maybe slide the axle in there too (if at's anywhere close to the right width).

Hopefully we will be caught up with other projects so we can start that one this coming summer (so, that's what, 3 years now and counting? ).

I figure on running the factory computer at first (VATS turned off and turn off the stuff that doesn't make it over to the Jimmy).

Maybe convert to Megasquirt if the turbo materialises.

Hmm I can't edit my last post, and I just noticed I forgot to include that it is indeed the 4200.

we have a gmc canyon with the 4200 for a company truck and it screems, you'll like it.

To keep the cost down would you have to buy a donor truck?
Since the computer and wiring is bolted to the engine and the computer gets hacked to remove VATS etc...

I bought a Trailblazer that had a tractor land on the back of it and removed engine /trans/wiring,/contol boxes/sensors/ etc and sold all of it for what I originally paid plus a 292 in trade because it scared the hell out of me. But I did get to keep a pair of nice bucket seats. Unless you're a computer whizz and wiring genius I think you'd be better off geting the donor vehicle. It's a lot of wires.

I have swapped in a few computer controlled engines to vehicles that didn't come that way before.

Getting the whole vehicle has been the easier route for me every time.

Not saying it's impossible, or even that much bigger a PITA, but there always seems to be some little part that you don't wind up with, when you buy just the engine (or engine / trans).

By the time you buy a "swapper kit" (what some of the wrecking yards call it when they sell you the engine, tans, accessories, harness and computer) you have somewhere around $3500 into it from what I've seen (ie Spaulding and others in the pacific northwest).

Even bidding against a twit that thought our trailblazer was 4X4 (we didn't know they made them 2WD till we saw this one at the auction, go figgure) and paying a delivery fee we have much less than that in it.

We also have the option of parting it out for $$$, so we may yet recoup part of our investment.

Buckets are nice (that's what the Trailblazer came with) but I would prefer one of the new 40/20/40 benches (but that's me).

i bet it was a four door, weight matters a lot to a small engined car

I havent read the manual [yet] but you would need
1-+12v and ground
2-starter +12v and solenoid wire to ign switch
3- +12v switched [ign switch]
4- +12v to fuel pump from ecm
everything else is wired to the ecm which is bolted to the intake manifold.
I guess a donor truck would be the way to go. Lots of engines[$1800 to $2500 ]in wreckers but no trucks I could afford.

I most likely lost power with the locked VVT, currently MS-EFI can't control the VVT so right now I'm stuck unless I shell out for a high end ECU. If I was staying with a stock engine there is no reason not to use the stock GM electronics.

efi-diy you have PM

I bet that Canyon has a 3500 5 cylinder engine and if its a two door truck, I agree.

Your turn...

E-mailed Jerry Weigt for a flywheel.
Going to try Pcmforless to disable blocks in the pcm.[ $100.00 I think]
Any other companies around to disable vat etc. in the pcm?

There's a tuner company, I'm spacing it at the moment (and can't seem to find them in my notes ) but they offer a computer programmer (PC based) that allows you to do all that yourself.

Maybe its HP Tuners Inc. the colorado owners website (lotta kids) they list several people in several states who have bought the software and are doing this for others. Check http://www.coloradofans.com for a list ( in their performance area). They claim you can change rev limits, timing, a/f, shift points/firmness, etc.

This site:
http://forums.hybridz.org/index.php/topi...ys/page__st__80
the last flywheel was sold. no more from Jerry? no answer to my mail.

Best to call Jerry, he's not so good with email.

Jerry emailed back. Buying the flywheel [so far so good]

All, just finished a nice PDF on how to do the wiring. Not sure how to host it yet. If you want a copy in the short term, give me an email address to sent it.
Thanks.

Thanks I'm just getting my first part [ flywheel] for this project. Two ebay service manual dvds on their way.
PM sent

@ limequat
It's people like you that make sites like inliners valuable with a great knowledge base.
And you make my hobby much more enjoyable.

Like I thought- not many wires when you get rid of the chaff.

I am just starting to notice these 4200s. I have seen some amazing videos about the performance capabilities on them.

But the first thing I dont want is a techno nightmare motor swap. Getting past the computer wiring and motor mounts and selection and installation of a transmission alone could mean countless hours.

Right now I am looking at my 250 in liner and a Muncie 4 speed slated for my 65 Nova. And you have all schooled me that it will take a lot of money for me to scare any V8 cars with a 250. I wont try to achieve that just yet.

So maybe the idea of big horsepower and good gas mileage plus less weight might make the 4200 swap a possibility somewhere in my cars' future, but for now I will sit back and take notes.

James,

Your within an hour drive or so from Winters, you ought to take a drive up and see Jerry Weigt. He has a 4200 with a distributor installed. So that takes 1/2 the techno away. A fuel only install is a lot easier to get running.

EFI

Oiler, glad to be of service!

Limequat,
You have a pm.......my email addy for a copy of your PDF.....if you don't mind. Followed your swap thread on trailvoy.....sorry to hijack your thread oiler

@ copo-rat Thats not a hijack.
The flywheel and bellhousing are shipped.

Got the flywheel and bellhousing. Nice pieces!