Hey guys, I'm new to this site and just wanted to say hi and let people know that my friend is building performance parts for the 4.9. He's selling performance intakes with carb conversion on them, performance distributors for carbonation, beautiful hand built headers. He really knows his stuff he used to race shifter karts and ford gts, probably one of the smartest people I know. Check his website out:
Johns49performance.com
I'm getting ready to do a 4.9 swap on my '84 coupe pretty soon. Was looking to see what everyone's feelings toward the 4.9 are I think it's one of the best swaps out there for the price.
Interesting! The two biggest problems with the 4.9 are the crappy heads, and the lack of performance parts. Now the biggest problem is the crappy heads. (And the fun that ensues when you try to remove/replace them.)
Good show!
------------------ Raydar 88 Formula IMSA Fastback. 4.9, NVG T550 Praise the Lowered!
Ya the heads are not the best but ported and polished with big Chevy valves should wake it up well. He is going to dyno his car in a couple of weeks. I'll post the results. We think it's putting about 320 to 350 to the flywheel. Fingers crossed
[This message has been edited by Raymac85 (edited 04-29-2016).]
Nice! I'm looking forward to seeing it. I don't know how restrictive the stock manifolds are, but the headers are interesting. I might be interested in a set of headers and a Y-pipe that connects to the exhaust in the stock location, and clears the Getrag shift linkage. (I had a 2.5" stainless system made that meets the Y-pipe in the stock 88 location.) To be honest, I'm not certain how much of a candidate I am for this, just now. I'm about to be armpit-deep in another car/project. Not doing a lot with this one, for a while.
Ya the heads are not the best but ported and polished with big Chevy valves should wake it up well. He is going to dyno his car in a couple of weeks. I'll post the results. We think it's putting about 320 to 350 to the flywheel. Fingers crossed
We have a clean low mile 4.9L sitting in the garage and I have had a chance to go through it.. You could put massive valves on that head and I doubt it would make that much of a difference. The ports themselves are very small (can't be ported that much) and the engine was designed to operate at a lower RPM and make loads of torque which it does. The only way to wake up this engine is with a turbo. A guy on this forum (PBJ) built a turbocharged 4.9L maybe 7 years back and ran 12 sec 1/4 mile times. That's the only 4.9L Fiero on record that gave this type of ET. For smooth highway cruising, good highway mileage and a decent 1/8 mile time, the 4.9L does its job well but for higher performance its just not made for it. If your friend breaks 200 HP on the dyno, I would be very surprised.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, 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 "
building a 4.9 to go fast in this car, most fail as the final gearing is set up for a smaller engine, this one makes low end power, gear it to use it.. not run bang,boom, bang through the gears and past the meat of the powerband at lowish mph The trans axle bolted to them is set up to move a heavy car and not driven like a sports car, most of the time so it's final drive is wrong.. plus they run taller tires.
[This message has been edited by E.Furgal (edited 02-16-2017).]
The Seville 4T60E is set up with 35/35 sprockets and a 3.33 differential. It works very well with the 4.9 in a Fiero. The majority of 4.9 swaps source the drivetrain from a DeVille. The DeVille trans is set up with 37/33 sprockets and a 3.06 final. The setup kills bottom end torque, compared to the Seville trans, resulting in poor off the line performance.
The Seville 4T60E is set up with 35/35 sprockets and a 3.33 differential. It works very well with the 4.9 in a Fiero. The majority of 4.9 swaps source the drivetrain from a DeVille. The DeVille trans is set up with 37/33 sprockets and a 3.06 final. The setup kills bottom end torque, compared to the Seville trans, resulting in poor off the line performance.
I'd take the 3.06 gear with a looser converter with lock up clutch.. say stall at 2400-2800
So just a update on my post from a while back. We finished building my Cadillac motor. I went with the 1990 4.5l instead of the 4.9l. The 1990 motor I used is the same heads and everything as the 4.9 just different stroke. Wanted to try for more RPMs. Heads where ported and polished. Biggest chevy valves we could cram in it. Valve springs. Ford roller rockers. 4.1l intake ported out and adapted for 4 barrel. Performance cam. One wire performance distributer. And aluminum fly wheel. Motor is in the car now and just finishing up the little bits. I'll post some pics.
Originally posted by jscott1: Are you sure you meant to say 200 HP? Aren't they supposed to make that bone stock?
My 4.9 w/5speed and Allante intake with Design 3 injectors made 180rwhp. Don't forget, dyno's expose drivetrain and accessory losses. That's why 140 hp Fiero 2.8's dyno at 115rwhp...
I think a 4.9 is a perfect upgrade for a duke-based car because it gives you essentially 2 dukes. For V6's, you can get more rwhp out of a properly rebuilt 3.4 or larger displacement V6. After my experiences trying to rebuild a 4.9 - I stay away from them... In fact I still have some polished 4.9 heads I'd like to unload...
[This message has been edited by lou_dias (edited 02-16-2017).]
A Getrag totally transforms the 4.9, but it really needs something like a 3.23 or even a 3.08 FDR. It blows through first gear rather quickly, and really wants another gear on the highway.
Even with all of that, the fun of driving it is still worth the shortcomings, without question.
