I have a bracket car that has me scratching my head a bit. Let me first say that I am asking a question(s) here right now but still need to do some work checking things out.
The car is a Chevy Monza 2+2 body style that is on a 2x3 frame with an A-Arm front on it (components are mostly Monza/Vega). The engine is a 434" SBC with the only GM part being the oil filter adapter. The engine was built and dyno'd by a very good engine builder (known him for 40+ years now) and he also put together my 555 BBC that sits in my rail. The engine came in at 747 HP - I don't recall the torque number but it was strong. This is backed up with a FTI Series 4 Powerglide that has basically all the good parts and a 1.80 first gear. The rear is a 9" Ford with 4.86 set and we ride on 31x15 slicks. The car weighs with driver at just short of 2200 pounds RTR. Best 1/8th mile is currently 5.71 @ 121, this was a 75*, 50% decent air day. Other runs that day were in the same area of performance. At that time, we had a TSI convertor that was supposedly built to match the dyno sheet of this engine. I have always felt that the convertor was too tight. While I find online performance calculators to be fun, I understand they are based on "perfect conditions" and given the information they will indicate that the car should be at 5.10 @ 138. My gut feeling is that the car should be somewhere around the 5.40 @ 128-132 mark. Based on that guess, the calculators tell me that HP is only in the 560-570 range.
The engine was dyno'd on race gas, we run it on alky with a 1050 QF carb. Sensor readings tell me that exhaust gas is in the 1250 range so I believe the jetting to be right. Cutting the threads off the plugs and checking the porcelain does not reveal anything out of order. Timing is at 32*, CR is just over 14:1. I have not done a leakdown or compression test yet but those are my first items on the list. The engine fires, idles at about 1050-1100 with a little temperature, there are no misses and pulls to 7000 easily. I can push the engine further but haven't as the power band of the dyno sheet showed 6300-6600. I don't have the cam specs in front of me but I can provide them.
Open to ideas.
The car is a Chevy Monza 2+2 body style that is on a 2x3 frame with an A-Arm front on it (components are mostly Monza/Vega). The engine is a 434" SBC with the only GM part being the oil filter adapter. The engine was built and dyno'd by a very good engine builder (known him for 40+ years now) and he also put together my 555 BBC that sits in my rail. The engine came in at 747 HP - I don't recall the torque number but it was strong. This is backed up with a FTI Series 4 Powerglide that has basically all the good parts and a 1.80 first gear. The rear is a 9" Ford with 4.86 set and we ride on 31x15 slicks. The car weighs with driver at just short of 2200 pounds RTR. Best 1/8th mile is currently 5.71 @ 121, this was a 75*, 50% decent air day. Other runs that day were in the same area of performance. At that time, we had a TSI convertor that was supposedly built to match the dyno sheet of this engine. I have always felt that the convertor was too tight. While I find online performance calculators to be fun, I understand they are based on "perfect conditions" and given the information they will indicate that the car should be at 5.10 @ 138. My gut feeling is that the car should be somewhere around the 5.40 @ 128-132 mark. Based on that guess, the calculators tell me that HP is only in the 560-570 range.
The engine was dyno'd on race gas, we run it on alky with a 1050 QF carb. Sensor readings tell me that exhaust gas is in the 1250 range so I believe the jetting to be right. Cutting the threads off the plugs and checking the porcelain does not reveal anything out of order. Timing is at 32*, CR is just over 14:1. I have not done a leakdown or compression test yet but those are my first items on the list. The engine fires, idles at about 1050-1100 with a little temperature, there are no misses and pulls to 7000 easily. I can push the engine further but haven't as the power band of the dyno sheet showed 6300-6600. I don't have the cam specs in front of me but I can provide them.
Open to ideas.
