Vehicle is a 65 Thunderbird. It has an Edelbrock carb. Nothing has been changed in over a year and it's gotten progressively worse. EVERY vacuum port has been blocked off. Nothing connected on intake ports or carb ports and it still does the same thing.

Update on the findings. The timing chain looks good. I have noticed a slight miss. Not a dead miss. It's especially noticeable around the 1500 rpm range. I haven't found any exact numbers but one website said the 0-60 time on a 65 tbird was just under 11sec. Checked mine over the weekend and it's best is a 12.88 just to give you an idea of what I mean by low power.

The car drives good. It's not a problem to get on the hwy and run 70. The acceleration is the issue. The best way I can describe it is like a 2 barrel with the timing set too low.

The compression test readings were incorrect. To make a long story short the quick connect fitting was the problem. Here are the new results from testing. Dry comp test all cylinders around 120. Leak down test was around 25% to 30%. Vacuum was 18. Fuel pressure 7.5lbs. Timming is @ 10. Power is just not there though.

Hello all,

I have a 65 Thunderbird with what is supposed to be a 390. I do know that the motor has been replaced at some point in time. The engine is extremely weak. Car struggles to spin the tires even on grass. I performed a dry compression test on the warmed motor with carb fully open. Readings were all really close but extremely low (84-91). The 6 month old spark plugs all look good, no sign of oil fouling. Car doesn't use any oil. Before I spend anymore time doing more testing I have a few questions. (I know very little about the FE engines)

1. Could their be any weird mismatched combination of parts that could result in compression being so low?

2. What web is the casting number located on the crankshaft?

I want to make sure this is actually a 390 before I go any further and I think the next step is to find out what the crankshaft is. Since I cant pull the pan without raising the motor I'm considering draining the oil and inserting my scope camera into drain hole to try and see the casting number on the crank. What piston would need to be at TDC for the web with the casting number to be at the bottom?

Thanks