compression too high?

[TicTacTone]

this is on my 85 mustang early model cobra 302 swapped (by that i mean it was a reman crate motor, 1967-68 gt350 spec long block), first a little history...i've burned through 8 starters or so in the past year (only driving the car in the summer and it got put on house arrest last august so i couldn't even finish off the summer driving it) i got a new one under warranty obviously, put it in, and it cranks for like a split second. when i let off i can see the pulley's backing up slightly, it feels like once it gets to the compression stroke the starter doesn't have the balls to turn anymore. it is a stock starter, the original compression ratio was 8.4 to 1 and the current ratio is 9.5 to 1 (i believe, i have to double check). i decided to pull the plugs, obviously because there would be no compression, with the plugs out, it spins just fine, quick, smooth, no noises, no shakes, would the jump in compression really be too much for the starter to handle??? i know it's not electrical, i tested everything and even re-soldered a couple of grounds just for the hell of it. i'm getting the right voltage everywhere and continuity where it needs to be. it is not the solenoid because i jumped it with a screwdriver and it did the same thing. the battery is putting out just over 12 volts and is rated at 770 cca. the starter i know is good because i tested it. i just want to make sure i'm on the right track before i spend the money on a high torque starter.

 

[Black87LSC]

Thats weird, 9.5:1 isnt THAT high...

 

[TicTacTone]

thats my opinion on it, but it seems like it is, unless someone :q:q:q:qed up the build and its higher but i doubt that. it pings unless i use 93 octane or higher though, which usually happens with 10 to 1 and higher but still, a stock starter should turn that either way.

 

[Frogman]

Compression test.

 

[1bad4.6l]

might need one those high torque starters. I had an issue like this on my 79 chevy 4x4. It's 10.5:1 compression. when i first installed the new motor i put the ground where it was on the old block. it cranked real slow and kept burning starters. after the 3rd starter i decided to do a little trial and error. so i started moving the ground from the battery around. origanally it was on the alternator bracket, when i moved it to a header bolt it spun fast like a factory truck should. I'm basically saying that I moved the ground from the battery closer to the starter and it solved the problem two years and stillthe same starter.:Bang also i can run 87 octane i just have to back off the timing but at the mudraces we run 110 in it.

 

[TicTacTone]

^^i'm thinking i need a high torque starter because i tried taking the ground directly from the battery to the starter and taking the starter cable and hitting the positive side and it did the same thing...i was hoping i wouldn't have to spend the money on a high torque starter because i like the lifetime warranty i have (i also took advantage of it lol)...i just didn't think that my compression was high enough to need one because it's not that high.