79 Cutlass Wagon G-machine build
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Can you say airplane gears I loved itAfter a couple months the TH250 started having issues so next in order was a new trans and some hp upgrades. I picked up a decent used TH350 from a friend and pulled a small block 406 from storage that I used to have in my Suburban. It had about 60,000 miles on the rebuild-
Stock 400 bottom end with ARP rod bolts
.030 8.7:1 eutectic pistons
Factory 400 smogger heads
Crane 266 cam, lifters, springs
Ebrock Performer and 750 Q-jet.
I swapped the cam for a Comp XE268 and the Performer for a Proform air gap dual plane intake and painted it GM corporate blue before slipping it and the TH350 with a stock converter into the engine bay.
Not a tremendous hp killer but it made decent torque and was a great daily driver motor. I installed it with Hedman shorty headers and a 3" single exhaust through a Flowmaster 40 series. On the dyno best run it made a little bit disappointing 221 hp and 282 ft lbs. The a/f ratio was pretty rich at the time and I think the altitude, low compression and junk heads were limiting it quite a bit.
Taking it to the track it ran pretty consistent 15.70's at 87mph. Consistent enough for me to win first place in points for the year in the Club Racing Series street tire class at Rocky Mountain Raceway. Overall our Utah Muscle Car Association club took 2nd place in street tire class. (Way to go boys!) My 60ft times were 2.4s, limited by the grandpa gears and stock converter. I've learned to live with it as it puts down 21 mpg highway without overdrive, but that's all changing soon.
What was the mph at the end of pull
At 4500 ft altitude that set up ran 15.70s @ 87 mph. Several years later I added 1.6 rockers, ported the factory smog heads a little and swapped to a different and better tuned 600 cfm carb. I also moved to 3000 ft altitude and went back to the track where it ran consistent 14.60's @ 100.XX . With a stock converter it still had slow 60' times but made up some time on the top end. I went through the lights around 4000 or so in 2nd gear. After that I installed a GN 3.42 posi rear, all else the same, and twice it ran 13.90, still at 100.XX. Unfortunately the by then 100K+ mile tired motor grenaded on the 3rd pass of the day, so I never found out if with some tuning I could pick up some time. It now has a new 406 small block and I'm under estimating it in expecting low, low 12s @ around 110 with the new engine. This engine ran mid 11's in my Nova, but it was about 200 lbs lighter, had 4.56 gears and a 4500 stall converter. Pumkinator now has a 3000 stall and the 3.42s mentioned above. Theoretically it should run around 11.80s but I'd rather underestimate and not be disappointed so the goal is hopeful for a 12.20.
I meant on the chassis Dyno at 6000 RPMs at the end of the pull my car was at 123 mph with only 3% slippage in the converter
Oh. Well, the speedo stops at 85 so... lol. Man that was a long time ago, if I remember correctly I took it to 6000 in 2nd gear. Supposedly that cam is good to "6500" so I revved it a little higher than I normally would just see the power curve, but as I had anticiapated it didn't make any more power past 5000 because of the limits of the heads and carb and all. According to the Wallace Racing calculator that's 124 mph. If it were 3rd gear that would be 189, lol.
After adding the ported heads and 1.6 rockers, on the highway in "Mexico" still with the 2.41 gears the car couldn't pull past 4600 in 3rd, which translates to about 144. I'm thinking I hit the aerodynamics wall at that point and it just wouldn't go any faster, no matter how long I had the pedal pegged. The new motor pulls hard to 7000 and torque peak is at 5000. With the 4.56 gears in the Nova I could easily hit 6500 in 3rd. I can't help but wonder if Pumkinator still had the 2.41s if it'd hit 160 which would be between 5100-5200. I think with this engine and the 3.42s Pumkinator should still be able to pull about 140+ which is getting up around 6200+. That's a long time to be spinning a stock crank 400 at those RPMs so I'm not sure I'll try that... more than once or twice, lol. 😎 I have a 9" rear that will eventually go in the car and I plan to have a 3.50 gear for autoX and 4.10 pumpkin for drag racing. Maybe I'll do a 3rd with like a 2.56 or 2.73 and see if I can get above 160 with it. The Silver State Classic race is only 3 hours drive from me so one day I'd like to run that event.
How much power does it take to surpass terminal velocity? I’m not sure, but Mr. Borg Warner might offer up an opinion.
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