If you have a J code I’m sure you have wondered about its stock performance. Here are my results. The variables that may effect your results are: this is a 68 convertible (so its heavier than a coupe) and my fat butt - 240 lbs - skew the results you can get with a GT/CS; 4spd and rear are stock original and have never been rebuilt; tires are Cooper Cobra 215/70/R14; engine is bored .30 over and not decked but thin gaskets were used, heads intake and exhaust are OEM not CNC machined or ported - no aftermarket parts except for the valve train (valves and springs are OEM spec) cam is a Edelbrock 2122and rockers are 1.6 CompCam roll trip rail CCA-1431-16; orig Autolight 4300 (voted as Fords worst carb ever!) rebuilt by Pony Carbs NM rated at 440 cfm - see my gallery (with an Autolight 4100 1.18 this would be a 14 sec car easy); distributor OEM, balanced by Distributor Dynamics Ca; Motive Industries duel exhaust - H pipe with transverse muffler and turn downs.

I finally ran the motor in my avatar Wednesday, has over a 1,000 miles now and I have been babying it to long. Made 9 passes trying to adjust the distributor (ping) and the secondaries (bog) on the 4300. I had always set the secondaries on the 5th bump as recommended but found best performance on the 7th. It was very difficult to launch due to the stock 3.0 open rear and thin 25.3inch tires - I smoked the tries on the start 4 times. Crossed the line in 3rd gear around 4800 + rpm. 5 passes were in the upper 15 sec range with the best pass at 15.586 / 89.321. This is a good 2-3 seconds faster than a stock 289. Tires chirped in 2nd and 3rd gear. This 302really is a hell of a block. I stomped on it hard - no wonder it's a favorite.

Copier drum is bad so here are the numbers:

React .637 (this is bad; best .032 but I was trying to get traction)
I1 2.358
I2 6.578
I3 10.051
MPH 70.532
E.T. 15.586
MPH 89.321

The only published editor results I can find to compare is the 1968 Mustang (MT) 390ci/335hp, 3spd manual, 3.25, 0-60 - 7.8, 1/4 mile - 15.20 @ 94mph (which is silly - a 3spd for a 390?) Does anyone have a publication that recorded 1/4 times for the 68 J code Mustang? Anyway I think this is close if not a little better than published factory performance. However, that 230 HP rating is way off. A different method was used back then but people still throw 230 around. According to the calculator at the above trap speed a stock 302 only produces about 177 actual HP. This will be the starting point for my WOLF in SHEEPS Clothing.

NEXT MONTH: I'm installing port machined OEM intake heads and exhaust for comparison.

In 1968, everyone used gross horsepower (at the flywheel). In 1972, everyone switched to SAE Net (at the rear wheels), which resulted in a big drop in the horsepower number.

Steve

In 1968, everyone used gross horsepower (at the flywheel). In 1972, everyone switched to SAE Net (at the rear wheels), which resulted in a big drop in the horsepower number.

Steve

Are you speaking about factory horsepower? If so, they have and never have used rear wheel horsepower, even today. That is an aftermarket modern phenomena.

Since there is no true way to measure horsepower, unless you want to have the engine pulled and put onto an engine dyno, the only way to measure horsepower and torque is to strap your car to a chassis dyno.

To reiterate, the HP/TQ ratings you see advertised and bhp, not rwhp.

I really appreciate you posting this!

Your scanner is lousy or you need to use more resolution, i couldnt make out the name of the racetrack.

My questions for you are:

what is the name of the racetrack?
what is the approximate elevation of the track?

When i started racing my car, i raced on 205/70R14 tires with 2.79 gear and a C4...i know your frustration LoL...keep improving those numbers!

Thanks for posting this, i wish more people raced...its really quite enjoyable
Thanks for trying to show your timeslip too, its important because BS is rampant
David Athans

Are you speaking about factory horsepower? If so, they have and never have used rear wheel horsepower, even today. That is an aftermarket modern phenomena.

Since there is no true way to measure horsepower, unless you want to have the engine pulled and put onto an engine dyno, the only way to measure horsepower and torque is to strap your car to a chassis dyno.

To reiterate, the HP/TQ ratings you see advertised and bhp, not rwhp.

Respectfully, we're both partially wrong, and both partially right. For years I've used a Chilton's for info, and come to find out, it has wrong info, in that it gives the wrong location for measuring NET horsepower. However, car manufacturers do use an engine dyno to get their horsepower numbers and in '72 they did switch to the net rating instead of gross, and still use net to this day. My point was that the "230 gross" (1968 number) may indeed be close to "177 net" (2008 number), and to point out the change in measurement method as a possible reason for the difference. In re-reading, I see that @Holmes already knows about the change, so I guess I should have just asked what measurement his desktop calculator uses.

Steve

Guys Yea it just dosen't sound mean when you say 177 HP. The calculator I used:
http://www.dragtimes.com/horsepower-et-trap-speed-calculator.php
It's hard to pin down an exact weight for the convertible. With my weight added it could be as high as 3500 but I just used 3300, so 177 might be a litle consevative. The published weight is with a 6 banger - with or with out fluids - I just don't know. I guess I'll just have to go to the truck stop scale.

David
Most of my track experience is with a 2000 GSX1300R. The ticket is from the Edinburg International Race Track (956) 318-0355 edinburgracetrack.com. Its a NHRA sactioned track - full 1/4. As you can see it was "Truck Trophy Night." This is deep south Texas, on the tip, 15 min from the International Bridge about 90 min from South Padre Island. Were probably 175 feet above sea level. I'm gona try to break 15 with the ported heads.

thee guys are throwing around some 1/4 numbers for stock 390 and hipo 289: http://forums.vintage-mustang.com/showtopic.php?tid/1484984/. Looks like mid 15 is good for my vert.

Guys Yea it just dosen't sound mean when you say 177 HP. The calculator I used:
http://www.dragtimes.com/horsepower-et-trap-speed-calculator.php
It's hard to pin down an exact weight for the convertible. With my weight added it could be as high as 3500 but I just used 3300, so 177 might be a litle consevative. The published weight is with a 6 banger - with or with out fluids - I just don't know. I guess I'll just have to go to the truck stop scale.

David
Most of my track experience is with a 2000 GSX1300R. The ticket is from the Edinburg International Race Track (956) 318-0355 edinburgracetrack.com. Its a NHRA sactioned track - full 1/4. As you can see it was "Truck Trophy Night." This is deep south Texas, on the tip, 15 min from the International Bridge about 90 min from South Padre Island. Were probably 175 feet above sea level. I'm gona try to break 15 with the ported heads.

i checked out the HP calculator you used on dragtimes.com...
my best e.t. 11.989
trap speed 111.79
Weight of vehicle with driver 3380lbs.

it told me mine was 378.1HP at the flywheel...well my car makes 384 HP to the Tires on a chassis dyno...dragtimes is not accurate whatsoever...

David
Its a problem for me because the closest dyno is 4 1/2 hour drive one way.
Is there a more accurate calculator or do you know anyone that can crunch my numbers? The DragTimes number is closer to to your RWHP than flywheel. I think the toploader has a 17% loss or it could be as low as 12 - don't remember but even at the lower number of 12% - 177 rwhp would be roughly 201-202 hp at the fly wheel. Sounds better.

The ticket is from the Edinburg International Race Track (956) 318-0355 edinburgracetrack.com. Its a NHRA sactioned track - full 1/4. As you can see it was "Truck Trophy Night." This is deep south Texas, on the tip, 15 min from the International Bridge about 90 min from South Padre Island. Were probably 175 feet above sea level. I'm gona try to break 15 with the ported heads.

Don't they have a scale there?

i'll get it weighed this weekend. FYI these results were on 25.3 tires and I'm wondering if the factory 26.8 (735x14.4) diamater tires would have given me a better time.

i'll get it weighed this weekend. FYI these results were on 25.3 tires and I'm wondering if the factory 26.8 (735x14.4) diamater tires would have given me a better time.

I don't think so. The shorter tires are effectively lowering your gear ratio, so as long as you are not having to shift right before you run out of track, the taller tire would probably slow you down.

David
Its a problem for me because the closest dyno is 4 1/2 hour drive one way.
Is there a more accurate calculator or do you know anyone that can crunch my numbers? The DragTimes number is closer to to your RWHP than flywheel. I think the toploader has a 17% loss or it could be as low as 12 - don't remember but even at the lower number of 12% - 177 rwhp would be roughly 201-202 hp at the fly wheel. Sounds better.

The only accurate way is to put your car on a chassis dyno...like these retarded calculators, engine dynos dont really mean much either because they typically dont have the accessories and the conditions are completely different than when the engine is in the car. You are probably safe saying your engine is putting out 200HP at the fly.

Ok sorry for the delay, work kids and all - finaly got to the scale. Fuel was a little lower by maybe a gallon but other wise same - scale showed 3280 w/ me at the wheel. So estimates were prety close. I got the ported heads, intake and exhaust manifolds back from Barnett High Performance. Going to tear down to short and instal port magic and see ya at the track.