Bluevette85

Is the only difference between these two pumps, the spring?

Can I put a high pressure spring in a M55 and get the same pressure as a M55A?

luvmy92

You might want to consider the 10552 which has 10% more volume with adjustable pressure. It can be used with the Canton 3/4" pickup (20-079) which will require a little modifying to mate up.

Mike

scorp508

I'm using an M55a with success right now. What is the price difference? Mine was only around $35 I want to say. So far this pump has been great in hard cornering autocross situations keeping constant pressure.

Bluevette85

The M55 is $12-13 and I have a spring already. I have a M55HV now but want to go back to the standard volume when I rebuild the engine. I see more harm than good with a HV pump in a rebuilt engine with normal clearances.

LD85

To answer your question, yes you can jus tadd the $5.00-$6.00 spring, or,,, you can put a washer in behind the spring too.

The M55A is good for a max of 75 PSI and the stocker will hit @60+ PSI according to Melling tech.

vader86

I've used the M55A for over a year and the pressure is perfect. It stays above 60psi easily when the engine is cold and warm idle pressure stays in the mid 40s. High rpm pressure will stay in the high 60s to mid 70s depending on temperature. I believe it cost me less than $20 from Summit at the time.

To answer your question, yes, you can put the spring in, just be sure to weld on the pickup for the new motor.