4 speed vs powerglide with 140hp?

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Chiro972b
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4 speed vs powerglide with 140hp?

Post by Chiro972b »

Hey folks, I have a real dilemma. I have been looking for a late model coupe and had one secured (I thought) for a good price and the seller pulled out of the deal. So, I bit the bullet and just sent a deposit check to a specialist dealer who has a very nice Monza with 140 and 4 speed. The price is high but after a bad experience I thought the safety of dealing with a dealer who has a good reputation was the better option.

Fast forward one day and I get an email from my accountant saying that I owe about $10K more to the IRS than I had expected.

There is a REALLY nice late model with 140 about 3 hours away from me that has a 140hp and powerglide and front disc brakes and is every bit as clean as the one from the dealer and by the time I pay for shipping from the dealer, it will be nearly $10K less, or $9K less if I lose my deposit to the dealer.

I really wanted a 4 speed, but my very first car back in the 70's was a 67 Monza with PG and I loved it, but as a teenager, wanted a 4 speed and ultimately found a 66 corsa without engine that I bought and swapped my 67 engine in and I loved that also.

I am 61 now and won't ever be racing, but I do still like spirited driving. So can anyone with a 140 and Powerglide tell me how it is to drive compared to a 4 speed? Cosmetically, they are both comparable, and the disc brakes on the PG car is a nice plus. Ultimately up to me to decide, but I'd love any opinions.
Thanks!

66vairguy
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Re: 4 speed vs powerglide with 140hp?

Post by 66vairguy »

I've never driven a 140HP PG car, but a fellow in our club has one and I've ridden in it. Just my opinion, but the four speed vs. the PG are different driving experiences. If you live in a congested city a PG car is great to just cruise along. If you are out where traffic is light you can enjoy the more spirited driving with a four speed.

The PG 140HP cars (if original) had a "different" 140HP engine! Also the PG was different to up shift at higher RPM. The PG 140HP engines had a milder cam that was shifted a few degrees from the manual camshaft timing via a unique crankshaft gear. Why? The consensus of experts say the changes were done to improve low end torque, yet allow the engine to rev to a higher RPM with the mild cam. So DO NOT expect 140HP performance to be like a 140HP engine behind a four speed manual.

I'd go further to suggest a 110HP PG setup would be nearly as good and much less complicated (two less carbs and less linkage).

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bbodie52
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Re: 4 speed vs powerglide with 140hp?

Post by bbodie52 »

:02: For most of my adult life I have always opted for Corvairs with 4-speed transmissions. The only Powerglide-based Corvair I ever had was a 1963 junk Corvair 500 that my father bought for me in 1969 to learn to work on, and I overhauled both the engine and the Powerglide transmission on it when I was 16. I later transplanted the engine into a 4-speed 1962 Monza that needed the engine, and that was the extent of my 2-speed Powerglide experience — which led to something of a prejudice against Powerglide Corvairs — until now.

I recently purchased a 4-door 1966 110 hp Monza sedan with factory A/C and a Powerglide transmission — and surprisingly, I like the transmission! It works well, and as a street-based, non-competition Corvair it is pleasant to drive and appears to be quite reliable. The only thing I don't like is the lack of a PARK position to lock the transmission, forcing total dependence on the parking brake cable. Perhaps my age (67) has something to do with my newfound Powerglide acceptance, but there it is. :tongue:

I would suggest that if the less-expensive Powerglide Corvair you are considering has a good automatic transmission that shifts well and has no sign of contaminated burned-smell fluid or significant oil leaks, you may be quite happy with a street-based Powerglide Corvair. If the dealer will refund your deposit based on the accountant-based revelation of a large, unexpected tax liability, so much the better. I doubt the government will spend your tax dollars wisely, but your purchase of the Powerglide-based (less-expensive) Corvair may be a wise and logical choice on your part! Carefully evaluate the less-expensive Corvair option, and move in the direction of your personal preferences.
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

Chiro972b
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Re: 4 speed vs powerglide with 140hp?

Post by Chiro972b »

Thanks guys. I do believe the PG car had the 140 from factory, but not completely sure. Since I posted this I did do some reading and found that the wrong 140 mated to PG is a pig at low RPM's. I've never driven a 140 at all to be honest. I had a corsa, but it was in high school 50 years ago and a buddy and I bought it together and he took the engine and I put my 67 monza PG engine in it since I wanted a manual. He already had bell housing, clutch, etc for his Corsa. My wife is telling me to stick with the one I have a deposit on, but the idea of paying that much more just for a 4 speed was already giving me slight worries and then the email from the accountant came in. Perhaps I'm still just in shock over that.

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bbodie52
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Re: 4 speed vs powerglide with 140hp?

Post by bbodie52 »

I believe there was some camshaft timing offset for some Powerglide/140 hp combos. I've never driven a 140 hp based Corvair with a Powerglide, so I could not speak from experience. Many 140 hp engines spend most of their operational time with only the primary carburetors in-use, with the driver seldom pushing the throttle hard enough to open the progressive linkage to bring-on the secondary carburetors.
This will give you some idea of the differences between the 140 hp engine and the 110 hp engine.

140 hp vs. 110 hp...
  • Same high-performance camshaft on both 140 hp and 110 hp engines. Low performance camshaft in the 95 hp engine.
  • Same 164 Cubic Inch displacement with same bore and stroke on all 1964-1969 engines.
  • Stronger, nitrided crankshaft on the 140 hp and 180 hp turbocharged engines. (Nitriding is a heat treating process that diffuses nitrogen into the surface of a metal to create a case-hardened surface).
  • On the 140 hp engine, a 4x1 carburetor arrangement, with two primary and 2 secondary 1-barrel carburetors, connected with a progressive linkage to open the secondary carburetors as you approach full throttle. (Equivalent to a 4 barrel carburetor on the 140 hp engine, vs. a 2 barrel carburetor (2x1) on the 110 hp and 95 hp engine).
  • Dual muffler, dual exhaust with larger exhaust ports and larger exhaust manifolds on the 140 hp engine. Single exhaust on the 110 hp and 95 hp engine.
  • 9.0:1 Compression Ratio in both 140 hp and 110 hp engines. 8.0:1 CR on the 95 hp engine.
140 hp Heads...

Image

Image

Image

It's all about better breathing at full throttle at the high RPM ranges. At lower RPM the big valves and dual exhaust don't make much difference, and the secondary carburetors are not open for business.


110 hp Heads...

Image
Brad Bodie
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66vairguy
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Re: 4 speed vs powerglide with 140hp?

Post by 66vairguy »

One thing not mentioned. It is absolutely necessary that a 140HP engine has the newer "deep valve seats" or sooner or later the stock seats WILL drop out. The car(s) you are looking at should have a receipt for rebuilt heads done by a known Corvair head expert. If not you are looking spending more money to get that done. Can you wait and see if the heads seats drop, sure - but when a seat drops the damage is more costly versus having functional heads re-built. Just my opinion.

Chiro972b
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Re: 4 speed vs powerglide with 140hp?

Post by Chiro972b »

Thanks for the input everyone. I think I’m going to stick with the 4 speed I’ve put the deposit on.

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azdave
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Re: 4 speed vs powerglide with 140hp?

Post by azdave »

66vairguy wrote:
Tue Oct 13, 2020 1:14 pm
It is absolutely necessary that a 140HP engine has the newer "deep valve seats" or sooner or later the stock seats WILL drop out.
I've owned 140's nearly all my life (since 78) and have a stable of them still including a 140 PG with working factory air that we drive through the summer desert heat in Arizona. I also have a 140 4-speed with working factory A/C that I have driven most of this hottest summer we've ever had in Phoenix. One might think I would have lots of stories about dropped valve seats but I have never had a single failure. If one fails I would probably just install a head from one of my parts engines. My own long-term experience shows that valve seats are not dropping like flies.

Your mileage may vary. ::-):
Dave W. from Gilbert, AZ
65 Corsa 140/4
66 Corsa 140/4
66 Corsa 140/4 w/factory A/C
66 Corsa 455 Toro V8
65 Monza Convertible 110/4
66 Monza Convertible 140/4
65 Monza 4DR 140/PG w/factory A/C
65 Monza 4DR EJ20T/5

1949chevy
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Re: 4 speed vs powerglide with 140hp?

Post by 1949chevy »

I agree with AZDAVE...I have a 140 PG 66 Corvair. No valve problems and I run this car pretty hard. Even just going to a weekly car show I will play with the traffic on the Interstate. I let them pass me, then I pull out into the open left lane and get on it and most of the time I look down at the speedometer and I see about 88-90 most of the time. I then let them all pass me close to my exit... a lot sure do look and wonder what I have.

I also run with about 5-6 guys going out of state to car shows in SC and TN. I follow a 65 GTO with 3-2's, the lead car. We are the two fastest drivers. I am followed usually by a 64 409-425hp Impala. At times I will pull up beside the GTO and play with him running about 75-80 and then get on it...then fall back to my 2nd position. We all laugh about my BS playing with the GTO when we get to the show, but they all know to respect it. At times, they will close up ranks and make me go to the back of the line...LOL...but its not long and I am back to 2nd place.

All this is so you know a 140/PG can run with the best of them. While it is sorta slow off the line, once you reach 15-20 mph then you become impressed with its running. By the way, I am running Roger's carb linkage and its set to engage the secondaries at 50% throttle. Mileage went from 24mpg to about 16mpg with that setting.

I say this as I have the right to say it with my comparison cars...my other car is a very fast 68 L-79 Corvette with close ratio 4 speed, 11:15 compression I have owned nearly 50 years. It was rebuilt in 1984 and has about 15,000 miles on it since then and I also have a 49 Chevy fleetline with a 283 I built with Z-28 601 small chamber big valve heads, 327 cam, quadrajet, etc, 700R trans and 3.42 rear end. It also is fast for a 283.

I am right in the middle of the mountains and about 20 minutes from the highest mountain east of the Mississippi and the Corvair handles the curves and steep hills very nicely...better than my other two cars as to curves.

Good luck with your decision...hope my post has helped you.

Wagon Master
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Re: 4 speed vs powerglide with 140hp?

Post by Wagon Master »

1949chevy, What rear end gear are you running?

1949chevy
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Re: 4 speed vs powerglide with 140hp?

Post by 1949chevy »

According to Bob Helt's book...my 66 Corvair has a 3.55 ratio rear end. I think that is std for a Powerglide 140. I just now installed a tach in the car but have not had a chance to check RPM VS SPEED YET. My 66 has been down for months now. After 10,000 miles, new pistons, etc I had a DEVES OIL RING COME APART, ruined one piston and got down into the cam gear and ruined that. Took a long time to finally discover that problem...engine kept tapping when hot. I cannot tell you how many times I had adjusted the valves, changed lifters, etc. Those DEVES rings caused 4 other pistons to have stuck OIL RINGS...causing many changes of spark plugs.

If you are asking about the Corvette, when it was painted a few years ago, my friend and I checked the ratio while up on his lift, it has positraction of course, the tire turned 3.5 times to complete one revolution. It will turn 55 mph in 1st gear as I have done that quite a few times...of course time in 2nd gear is only 2-3 seconds and time to shift to 3rd.

Here is the Corvette, my cousin wanted to take it out after winter storage...carb power valve was not working at this time but...turn up the sound, bad cell phone but you still can hear it wind quickly.

http://www.youtube.com/watch?v=TgBFh7m_45w

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