GM 4200 inline 6 cyl engine swap

Learpilot · December 23, 2010, 07:09:16 PM

My son wants to put a Chevy Trailblazer Vortec 4.2 engine with a 4L60E transmission in his 1965 Chevy C-10 short bed truck. He has a 250 cu.in. with a three speed transmission. He wants to use the EFI and transmission computers.
How hard is it to modify the wiring harness ?
Has anybody used this engine in a engine swap ?
Thanks in advance !!!
Rick

57larry · December 24, 2010, 04:10:41 PM

go with a 283 and a turbo 350 instead

Fat Cat · December 24, 2010, 04:29:32 PM

Quote from: "57larry"go with a 283 and a turbo 350 instead

Why just because it suits your tastes. Some of us like computer controlled engines and strive to use them in our rods.

I don't know anything about the computer systems on a Trailblazer but they can't be much harder than those of an LT-1 or a Tuned Port motor.

I have a Tuned Port 305 for my 47 Chevy and an 4.3 Liter LT-1 for my 82 Lynx and have no worries about how easy they will be to install and even less work on maintaining than most cars.

Larry quit being such a traditionalist snob and accept that some members of this forum like computerized motors. There are even a few on here with some experience that could be valuable to others.

GPster · December 24, 2010, 05:22:18 PM

I can stand in the middle and be wrong on both counts. I've got a fresh '85 4.3 (plus .030) V6 that was made for a quadrajet style throttle body. I converted the distributor to be a normal HEI. I had it running on the stand with a regular carb and if someone doesn't talk me out of it that's probably the way that I'll use it. Because of the year it's not a Vortec motor so it's got the regular Chevy bell housing and flywheel bolt pattern. Of course I'm planning on going the other way too. The Jeepster is now on an S10 frame and will be running the stock 2.5L 4 banger in it. I got the truck whole and kept the stock wiring harness and computer and the gas tank with fuel pump and it's relay and all it's line and hoses and the instrument panel and the steering column and the throttle linkage and the brake pedal with switches but I didn't get it with the catalytic converter. Now I drove it out of the junkyard under it's own power without a converter so I know it didn't keep it from running but I'll probably be greeted by red light when I get it running again. Wayne directed me to a site where I got a wiring diagram for it (all 31 pages) and leaving out all of the circuits that I won't use I got it down to nine pages. Because I bought the truck whole I was fortunate because I had enough data to get the correct wiring diagram because it relies on the build date and plant that the vehicle came from. I sure there's enough smarts here that if he gets all the right parts someone here can help him make it a runner but it might be more than "I'll ask dad" project. GPster

tomslik · December 24, 2010, 06:29:11 PM

Quote from: "Learpilot"My son wants to put a Chevy Trailblazer Vortec 4.2 engine with a 4L60E transmission in his 1965 Chevy C-10 short bed truck. He has a 250 cu.in. with a three speed transmission. He wants to use the EFI and transmission computers.
How hard is it to modify the wiring harness ?
Has anybody used this engine in a engine swap ?
Thanks in advance !!!
Rick

i see the oil pan possibly being an issue (i've never paid any attention to a 2wd colorado to know if that would help BUT make sure you can pull the pan easily, as you'll be there to reseal the frt cover (they like to leak coolant by the water pump)
aside from that and the 400 dollar computer controlled clutch fan, i don't see 'em with a bunch of problems, sounds like a good choice for the project!

Charlie Chops 1940 · December 24, 2010, 06:53:20 PM

I'm on my 2nd TB since 2002 with the 4.2L and I have been very happy with the drive line. I haven't seen much in the way of performance enhancers though and I'm grossly ignorant when it comes to computers, automotive or otherwise. However, I think one of the 4.2's would be an excellent transplant in an early rig. I change the oil and filter on mine and that's been about it. The oil pan is long and of a singular depth but I've never measured it. The engine looks tall but I'm not sure that would be a problem.

How about a chassis swap? I would think the width would be good and the wheelbase shouldn't be extremely hard to adjust.

My 2007 has 291hp and 3.43 gears. I pull around 5000 pounds with my track roadster in the trailer and it handles that easily and gets in the low 13's, better down hill. Normal highway mileage touches the low 20's and I'd guess the overall average around 17. It's strong runner for its size.

Just some thoughts...

Charlie

Crosley.In.AZ · December 25, 2010, 08:39:42 AM

We had a 67 Nova with turbo charged 4.2 engine , 4l60e trans in the shop months ago.. it was controlled via a FAST EFI setup. Trans was on a TCI controller

Learpilot · December 25, 2010, 08:59:51 PM

Quote from: "Crosley"We had a 67 Nova with turbo charged 4.2 engine , 4l60e trans in the shop months ago.. it was controlled via a FAST EFI setup. Trans was on a TCI controller

THANKS for all your input !!!! My son has shown me the way of EFI on my 36 Dodge and he has EFI on his '68 Camaro with a 396 5 speed.
Thanks , Rick

Crosley.In.AZ · December 26, 2010, 12:11:39 PM

Back around the 1990's, I used a 1989 chevy truck TBI setup in a 1970 chev 4x4 truck. I bought OE type manuals from I think Helms (?) to strip out the un-needed wires. Manuals cost like 120.00 US as I recall

It was quite the feat for a non tech guy as I am. The 4200 engine controls must be 3 times the stuff as I dealt with.

Guy I work with uses MSD 6LS controller on the LS series engines and a carb intake.

Your son has to be able to figure this out... sounds like a good idea for an old truck

BFS57 · December 27, 2010, 02:12:07 PM

Hello;
Some handy info for you.
The I-6 as it is known is cheap to come by in a wrecking yard.
The computer, I don't know about.
The oil pan may need modified as it is quite large (7Qt)
The mounting has to be very solid and you must use the stock mounts as they are a combination of mount and heavy duty damper! Very Important!
Other than that, I hear that a web site called "straightliners" should have some info also the "trailvoy" website might offer some info as well.

Bruce

Crosley.In.AZ · January 08, 2011, 11:58:50 AM

Watched a video a friend posted on throttle body opening rate of the 4.2 engine. Unbelievable how slow the throttle blade opens in OEM programing.

he ramps up the % of response to instant... BIG difference

here is vid link:

clik here

video is about 1 minute 50 sec

jaybee · January 08, 2011, 10:46:14 PM

That's a remarkable difference. It must be a means of dealing with drivers with, um, less than optimal reflexes.

Bruce Dorsi · January 09, 2011, 10:00:26 AM

Quote from: "Crosley"Watched a video a friend posted on throttle body opening rate of the 4.2 engine. Unbelievable how slow the throttle blade opens in OEM programing.

he ramps up the % of response to instant... BIG difference

here is vid link:

clik here

video is about 1 minute 50 sec

Thanks for the link, Tony! .....A picture is worth a thousand words!

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Crosley.In.AZ · January 09, 2011, 10:22:14 AM

Quote from: "Bruce Dorsi"
Quote from: "Crosley"Watched a video a friend posted on throttle body opening rate of the 4.2 engine. Unbelievable how slow the throttle blade opens in OEM programing.

he ramps up the % of response to instant... BIG difference

here is vid link:

clik here

video is about 1 minute 50 sec

Thanks for the link, Tony! .....A picture is worth a thousand words!

He plans on using this throttle body setup on a Corvair. He tells me wires are easier to run than a cable back to the engine.

Mike does wacky stuff like this. He also tells me to step into the 21st century