3.8 - 4.3

recently I decided to downsize from 350 chevy to 4.3 in my 38 dodge. The motor going in is 4.3, mid 90's TBI all computer contolled, I wanted it carberated so I pulled the intake and carb off 229. Ports are a little smaller but bolted up. Then I took 229 HEI, and thinking one engine is oddfire and the other is even fire I put magnetic pickup out of straight 6 HEI in the distributer. I also used the flex plate off 229 on 350 turbo tranny. Havent gotten it started yet but am beginning to doubt my thinking. Any imput ???


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Not sure what ur asking? I know I would have kept the 350. Whats your reasoning for the 4.3?

Reason for downsizing is simple, economy. Health issues have forced me into a fixed income.( I'm not whining) with stock 350 2jet, 350 turbo and 2:76 gears it got about 18 mpg, hope to get it up to about 22 mpg.
My question was on the odd-fire even-fire timing and balance. 229 was 81 malibu engine and odd-fire engine, 4.3 is mid 90's and I ASSUME it is even-fire.(split rod journals), thus the different mag, pickup and question the balance of flex plate. If it is independently balanced no problem, but if flex plate is part of balanced assembly I dont want it bouncing up and down.
Thank You

This is a good candidate for the new Electronic forum, moving.

__________________
''Life's tough, Pilgrim, and it's even tougher if you're stupid.''---John Wayne

Midnight Sun Street Rod Association

i think what you're concerned about is the distributor compatability between the two engines?

If that is the case, then NO you cannot and should not use the 3.8's distributor in the 4.3! This is due to the even vs. odd-fire differences. At the very least the "star wheel" will have to be swapped for an even fire "star."

i think all 3 engines---200,229 and 262 are internal balanced but i will get back to you on that.

the star wheel (magnetic pick up assembly) I put in the distributor came out of a straight 6 (250) and is even fire. My primary concern is with the balance. The 262 had a stick shift flywheel, as I am using a 350 turbo tranny I used the flex plate from the 229. The question is whether it is a balanced assembly or independently balanced ? ALSO if it is a balanced assembly can this be fixed by changing the harmonic balancer ? HELP PLEASE



IF YOU CAN CONCEIVE IT, YOU CAN ACHIEVE IT

The 4.3 swap may help, but think on this for a while:
I had a '78 Camaro 350 doing 8 MPG. Of course I tried swapping the carburetor and such, but the only thing I did to it that made a dramatic improvement in MPG was a $100 700R-4 from a salvage yard. I did a shift kit, a new filter, and a lockup kit, plus had to get the driveshaft shortened. Final cost under $500. Final MPG, with no centrifugal advance working in my '78 HEI: 25.1 MPG at 65 MPH. This was the same Q-Jet that was giving me 8 MPG before. This was with the 5" rear spoiler, 215/60R15x7 front, 235/60R15x8 rear and a 3.08:1 axle.
As for the 4.3, I had 2 give amazing mileage. The first was in a '94 Chev C1500 W/T, a full-size, regular-cab, long-bed 2WD pickup with a/c, 4L60E ( same as 700R-4 ) and 3.73:1 axle on 235/75R15x7s. It averaged 23 MPG, with a best of 26.
I then had an '89 S-10 2WD regular cab short bed with every option. I had to swap the rear axle, and then I had to get the speedometer corrected. I consistently got 28 MPG at 70 MPH with this: TBI 4.3 / 700R-4 / 3.42:1 / 235/60r15x8s, lowered 2", tailgate down, and 4" front airdam.
But the performance difference between my S-10 and my Camaro was well worth giving up a few MPG.
A week before I sold that Camaro I finally rebuilt the distributor. I know that had I re-checked the MPG at 60 MPH, it would have showed 27. Put it in a third-generation Trans Am, it would do 28.
Sell your 4.3, reinstall your 350, sell your TH350, install a 700R-4, swap your 2.73:1 gears for 3.08:1 gears, and keep the car fun as well as efficient.

Give me a few hrs.

All 200, 229 and 262 cranks are INTERNALLY balanced; So, you can use any small block flexplate(the 229 is good) that is not balanced---except for the 400's. This is according to the 90 chevrolet power manual chapter 4, pg 19. i know it's not real current but all those engines were produced before 90 and the thus info is still correct regardless.

Good luck and go for it; i'm leaning towards this engine for hi-po work believe it or not.


P.S. correction---the correct term is semi-even fire for the 200 and 229 because cylinder firings happen at 132 degrees, 108 degrees, 132, 108 and so on. The 262/4.3 is even fire because firings happen each 120 degrees---you probably already knew that. And the odd fire is the hardcore common pin crank for hi-po work---150, 90, 150, 90 etc. firings.

Did you notice the 229 2 bbl. intake is a 360º ('open plenum') design?

I think the only way you'd see much of an increase in MPG is if you kept the EFI on the 4.3L V6. You could have swapped a Dualjet carb and intake to the 350 and gotten about the same results IMHO.

Your scheme for the distributor will work fine. The problem comes when the 4.3L even fire distributor is used on the semi-even fire 200/229. Even the info on Skip White ebay ad for their V6 distributor says it'll work on both the 4.3L and the 229cid V6 engines. I wrote them to ask about this, along w/a reference to a chrome moly ring that's actually molybdenum inlaid. They responded on the rings (said they'd correct the ad) but never said squat about the distributor.

Thank you VERY much for your responses. I was not aware of my own ignorance. I thought if it wasn't even fire it was odd fire, thank you very much AGAINST ALL ODDS for semi-even-fire. Every question answered spawns 3 new questions, I'm well on my way to being the most ignorant man I know.


Thank you very sincerely
Rusty Rocker-panels

It isn't so much you know what you like, as you like what you know !

Here is a previous post on the 4.3L V6 distributor:
http://www.hotrodders.com/forum/wha...hevy-77568.html

Don't use the 229 flex plate on a 4.3L, you will end up with a shaker. The 4.3L V6 and the Vortec 350 sbc have an external weight in the flex plate for balancing. Get one of these flex plates.

GM Changes to the sbc (From GM website):
1986 – The rear main seal was changed from a 2-piece rubber design to a 1-piece rubber design that used a mounting appliance to hold it in place. This necessitated a change in the flywheel/flexplate bolt pattern, as well as the need for an externally balanced flexplate/flywheel.

The 229 flex won't bolt up to a 1-piece rear main seal crank.

Correct, but he did say he used it on his mid 90's 4.3L? Did he file the holes?