Been discussed a thousand times. I've got the 2.8 that's in the car now. Got a 4.3(97 vortec, 50K miles) for free with ECU, and Harness from in law's. Got a OEM Garret T3 turbo 60 trim Comp side, rebuilt and balanced for free. Picked up a T3/T04E .63 turbine side, .50 comp side, brand new for 50$.(eBay turbo i'm sure) So. with this info, I must choose. It's a daily that I take to Autocross every chance I get. 80mile round trip a day commute. If i keep 2.8, I'll keep the TH125 for now. 4.3 will get 4T60. So lets hear your opinions.
4.3 would require an adapter plate as the bell housing bolt pattern is not FWD. 4.3's are awfully good engines - with a turbo it would be kinda Scyclone -ish.
Be sure to have the 4T60 upgraded (and the 35/35 sprocket & chain and the 3.33 diff installed) during the rebuild - the turboed 4.3 would kill a used stock one.
[This message has been edited by olejoedad (edited 10-07-2011).]
The adapter plate mates the larger bellhousing pattern of the SBC (and 4.3) to the Fiero (aka Metric) bellhousing pattern. It also spaces the engine forward to properly locate the flywheel in the Fiero bellhousing.
[This message has been edited by phonedawgz (edited 10-07-2011).]
I understand what the adaptor does. I'll be useing a plate in the front that will serve as engine mount as well as acc mounts. In the rear it will serve as adaptor and rear mounts. The only single mount in the engine bay will be rear trany mount.
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09:55 AM
Dennis LaGrua Member
Posts: 16083 From: Hillsborough, NJ U.S.A. Registered: May 2000
I understand what the adaptor does. I'll be useing a plate in the front that will serve as engine mount as well as acc mounts. In the rear it will serve as adaptor and rear mounts. The only single mount in the engine bay will be rear trany mount.
Single trans mounts used with higher horsepower engines put an enormous amount of pressure on the cradle. They are used this way but always with front and rear dog bones. As for mating the 4.3L to your trans; V8 Archie should have everything that you need. He's been making adapter plates & kits for many years and will know exactly what you need.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, ZZP Intercooler, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
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10:27 AM
engine man Member
Posts: 5316 From: Morriston FL Registered: Mar 2006
For front, but with ACC's mounted, and motor mounted to cradle through the two ends of the plate
Same for rear, but will serve AS adapter, AND two motor mounts same as front.
As for the single rear trany mount. I see what your talking about, The front of the tranny will be supported by the rear plate, and if I need to use two rear mounts as well, I'll do that. All mounts will be polly(it is a daily)
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10:22 AM
fieroguru Member
Posts: 12584 From: Champaign, IL Registered: Aug 2003
The 4.3's fit the fiero engine bay quite well and with the right 4T60 will result in good MPG. My 92 4.3CPI/4T60 swap would hit 25-28 mpg on my daily commute and up to 32 mpg on the interstate.
The current 4.3 swap in progress (currently on hold for 2 other engine swaps) is a 97+ block/heads, 92-94 CPI intake with flipped upper plenum and individual injectors, 92-94 roller cam all bolted to a F40 6 speed:
With the FWD tranny attached to the 4.3, the Mount/adapter plate will only be able to be attached to the front cradle crossmember, as the auto trans extends along the side of the block on the trunk side of the engine.
The two transmission mounts will suffice to anchor that end of the drivetrain to the cradle. Do yourself a favor and don't overcomplicate your install.
