Author Topic: Horsepower drop in 1973  (Read 3876 times)

lakeman360

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Horsepower drop in 1973
« on: October 23, 2009, 10:41:51 AM »
Can anyone tell me, what was done to drop the HP in 1973 to 140 on the 302 2bbl?  I didn't think that they had picked that model to reconfigure the HP rating, as it has always felt so much slower than the previous models (even allowing for the weight gain.)  I've owned this convertible for more than 20 years and have always considered reversing this indignity.  Thanks.  I appreciate any and all input.

Jeff73Mach1

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Re: Horsepower drop in 1973
« Reply #1 on: October 27, 2009, 10:57:54 AM »
The big change was to the HP rating system which went from gross to net (more or less)

I have a 73 351C 4V, but in the past I had a 73 with the 302 2V and the FMX automatic.

I made the following changes that took the car from sluggish to more than respectable.

Carter AFB 4V Carb on Edelbrock Performer intake, Mallory Unilite ignition conversion, Mallory performance coil, Heddman headers and the most important change was to replace the center section of the rear end to change the gears to a 3.40 gear.  This was all 20 years ago and some things are still the same, while others have changed. 

If I was working with a 302 now I would use the GT 40 heads and a matching intake, a Holley with electric choke of 600-650 CFM with vacuum secondaries, I'd use Hooker headers as they seem to fit better, and I would probably go with 3.73 gears.  I would upgrade the distributor to a HEI ignition and I have found none better than Performance Distributors out of Memphis.

If you are at the point of doing an engine rebuild a camshaft change will help. Roller cams free up horsepower, but I do not know if a roller block will interchange with your earlier style block.  You would need to research that if you wanted to go in that direction.

I would actually consider going old school on the cam and using a solid cam-but you will need studs and guideplates added to the heads.  It will give you an engine capable of running higher RPM's without valve float.

You might want to talk to some folks that are familiar with stall speed on torque converters and see if that needs to be adjusted to any changes you make. 

Soaring

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Re: Horsepower drop in 1973
« Reply #2 on: October 27, 2009, 09:09:49 PM »
That was the year about when the gas lines got really long because of a drop in oil imports to the United States, and all car companies had to build more gas efficient engines.  The biggest difference is the compression ratio.  Less compression= less horsepower. 

Tim175

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Re: Horsepower drop in 1973
« Reply #3 on: October 27, 2009, 09:45:09 PM »
Yeah but now a days they have low compression engines with crazy horse power. Saw a 302 with 700+ HP running on pump gas ;D

Soaring

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Re: Horsepower drop in 1973
« Reply #4 on: October 28, 2009, 06:13:15 PM »
I was talking about USTA, as in 1973.  Yeah, today's close ratio engines don't need so much compression to produce the power they now get.  We would have never ever dreamed of running 5-W-20 motor oil back in 1973. 

lakeman360

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Re: Horsepower drop in 1973
« Reply #5 on: October 28, 2009, 06:51:08 PM »
Thanks for your ideas.  I've been hesitant to do anything about it until now, as the car is original and the engine has never been cracked.  But, what the heck, performance is performance.

 

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