I have heard these engines were detuned down to about 140hp from 220hp the previous years. What is the difference? Just Heads?, Pistons? Cam, Everything? I'm hoping to but a 1973 Comet with an original 302 engine and would prefer 220hp vs 140hp, so if all I have to do is swap the heads thats easy, but if the pistons and cam are different also it's not worth the trouble, I would just do a roller block swap. Anyone know? And what are the best bang for the buck mods to that engine. Headers? Intake and Carb? Cam? Gears and Posi? Trans kit and Converter? I will still eventually do a 5.0 long block swap, but for the meantime while I do suspension and paint, I would like the extra 80hp
I think the main difference was mainly that they used to be measured at the motor, and switched in 72 to measuring at the tires. I also believe there was a slight drop in compression. A few people said the motors are closer to the same h.p. than most people think.
That plus they backed down the timing for emissions. I don't think there is that much difference though I'm pretty sure my 72 was close to 140 when it was stock. As for bang for buck, first things first. A general tune up is the best place to start. New plugs and plug wires, new rotor cap and button for the distributor, new coil. You can bump the timing up between 10-14 btc depending on your set up and the gas you're using. After that get a free flowing exhaust, I've 2 1/2" pipe with flowmasters but thats a highly debated topic on here My first time around I picked up an edelbrock carb, performer intake, performer-plus cam, along w/ the accessories like a new double roller timing chain and a K&N air filter. It dyno'ed at 180 HP 240 ft/lbs torque. Cost me about $800 depending on what else you run into. If I had it to do again I would have gone with a more agressive cam and a Weiand Stealth intake. I just redid the engine and reused the carb so thats a good investment regardless of what else you do.
That is pretty much the story that I have heard. The went from gross horsepower ratings to brake/net horsepower (both measured at the flywheel) that year AND the compression ratio on a lot of engines dropped, then starting in 1973 a lot of the American made cars started getting all the Smog/emissions equiptment that further drug the HP ratings into the gutter. This link explains it a little more in detail and also explains why there was some confussion http://en.wikipedia.org/wiki/Horse_power
It definitely woke it up, we like to call it seat of the pants faster . I could have spent the same amount and gotten a little more out of it. And for the record, that 240 ft/lbs is where the big jump was. I'm betting that with a Stealth intake and a little bigger cam I could have hit 200hp for the same $. As for the mustang that'd be a hard call, depending on type of transmission, gears, etc. I'm not sure of the mustang specs.
The Fox bodies are about 225hp and 300 torque, but weight a little more I think, so should be close. So I thinking now leave the long block stock and run a stealth with a carb, headers with mufflers, trans & converter. At least till I can find a nice 5.0 long block.
That should help it breathe better, just don't know what kind of gains to expect without changing the cam. Let us know if you get HP numbers from it. Got any pics yet?
Food for thought Why put an old 302 in a fox body? IMO unless your keeping an old car semi original a new style block is better. They dont have the heavy 2M cranks, they have 1 piece rear main seals, they have more efficent Hdy roller cams, heads have hardend valve seats. Also if your converting dont forget your car probably has serpentine belts, this means that even if your lucky and the lower pulley fits in the correct position with the old style hubs then you still need to change water pumps because they turn in different directions. Can you just switch hubs? I dont think so because arent the older 302's balanced for 28 ounces? It can be done, but seems like a hassel expencially if you plan on putting a 5.0 liter back in
I think he was just comparing the output of the Comet to a fox body Mustang. I believe he intends to tweak the engine in the Comet and eventually put a newer longblock in it.
Just taking about the differences in the two, I have had 2 Fox bodies and they are great to hotrod with the aftermarket avaliable, but these comets/mavs are new to me, and yes I took two pics of the car on monday, it's not mine yet, it's a little old ladies car, 90,000 original miles, air conditioning even works, but has vinyl top and I can see rust damage, but it is a california car which is where I'm at, so hopefully the roof can be saved. Trying to get the car for $1000 bucks, it's white with brown interior and that dreaded vinyl top, nice shape though, and I will be parting out a lot of the stock parts like the AC and seats and stuff (if I get it)
The real difference between the 1969 and 1973 302 is a combination of ignition timing, compression, and camshaft. Along with those changes the fuel air ratio was changed (leaned out) and exhaust gas introduced into the mix to make it fire more effectively. The method used to monitor or rate the HP was also changed to conceal some of the de-tuning. the easiest way to gain some of that HP back is to tune the ignition and add a carb from a 1969 302. If you are going to rebuild your 302 then at least use the components used on the earlier models - or go aftermarket and increase compression even further with a good increase in duration and lift on the cam too.
im only guessing you would give a mustang a run for its money... 5.0 means 5 litres of ford power vs those 4.6 my car makes me feel fast.... i havent raced a mustang but a honda civic and a 4.3 chevy will do!
Here are 2 pics of the car, it is parked in a tight spot and these are the best I could get, but it's pretty clean and I will paint it white with a black Comet GT stripe.
