This rubber trunk mat available for my 57 Belvedere?

[Finsinthemirror]

Mine is a 318 and is not currently running and I'm super short on time to do much about it at the moment.. long story. The poly motors are like, from memory range from 8.5:1 to 9.25:1. I'd think that 100-120 would be ok but for a rebuilt engine that may be low. When it was machined was and decking done?

 

[Rusty Muffler]

Mine is a 318 and is not currently running and I'm super short on time to do much about it at the moment.. long story. The poly motors are like, from memory range from 8.5:1 to 9.25:1. I'd think that 100-120 would be ok but for a rebuilt engine that may be low. When it was machined was and decking done?

Unknown, I bought everything with the rebuilt engine out. I can see the original cam and pistons have not been replaced, but it's so clean inside (it had to have been boiled out and totally taken apart) that I figure they did what any reasonable person would do and that would be to spec it and replace anything that needed replacing such as rings and valves. The grandson didn't have much info on what was done but the complaint was low compression to the point it wouldn't run. Well it runs fine now, doesn't smoke, leak or use oil. Plugs look good.
Anyone else that has checked their 301 compression?

 

[57fury440]

If it is running well, I wouldn't worry about the compression numbers. They are pretty consistent and it doesn't smoke. I think the 2 barrel 301 Poly was rated at 8.5 compression ratio. The 290 HP Fury 318 was rated at 9.25. None of the Plymouth Polys were rated higher than that. I had Jahn's pistons in mine when I raced it with the 318 Poly. Those pistons were rated at 11.5 if I remember correctly. That was around 1966 and there were quite a few parts for these engines available. The Plymouth Polys are nice engines, their only drawback is they are a little on the heavy side weight wise.

 

[Rusty Muffler]

If it is running well, I wouldn't worry about the compression numbers. They are pretty consistent and it doesn't smoke. I think the 2 barrel 301 Poly was rated at 8.5 compression ratio. The 290 HP Fury 318 was rated at 9.25. None of the Plymouth Polys were rated higher than that. I had Jahn's pistons in mine when I raced it with the 318 Poly. Those pistons were rated at 11.5 if I remember correctly. That was around 1966 and there were quite a few parts for these engines available. The Plymouth Polys are nice engines, their only drawback is they are a little on the heavy side weight wise.

Yes, I think about 60 pounds heavier....

If it is running well, I wouldn't worry about the compression numbers. They are pretty consistent and it doesn't smoke. I think the 2 barrel 301 Poly was rated at 8.5 compression ratio. The 290 HP Fury 318 was rated at 9.25. None of the Plymouth Polys were rated higher than that. I had Jahn's pistons in mine when I raced it with the 318 Poly. Those pistons were rated at 11.5 if I remember correctly. That was around 1966 and there were quite a few parts for these engines available. The Plymouth Polys are nice engines, their only drawback is they are a little on the heavy side weight wise.

Thanks 57, I posted a new thread to find out. People are anxious to mention what they think, but I want to see from actual owners of the 301 to find out. I've got a 68 GTO 400 engine with a cam and the psi #'s are 120 a cylinder and it goes like a bat out of hell. From my 65 years experience, I would have figured the compression should be around 180 psi. but it doesn't smoke or use oil either and I can't get it to ping on regular gas, go figure!

 

[Finsinthemirror]

I'd be happy with 120 per cyl.. especially for a hone and re-ring. If the 2 cyls with lower numbers are right next to each other I might question the head gasket seal or re-torque the head bolts but if it doesn't smoke, no blow by, use any fluids, and starts easy I'd think it's good enough to rumble..

 

[Rusty Muffler]

I'd be happy with 120 per cyl.. especially for a hone and re-ring. If the 2 cyls with lower numbers are right next to each other I might question the head gasket seal or re-torque the head bolts but if it doesn't smoke, no blow by, use any fluids, and starts easy I'd think it's good enough to rumble..

2 similar cylinders are #4 and #7. After reading my old posts you sent me (thank you), I need to wait another 500 miles or more to check compression again.

 

[Rusty Muffler]

2 similar cylinders are #4 and #7. After reading my old posts you sent me (thank you), I need to wait another 500 miles or more to check compression again.

Sorry, those are the two high #'s 110 psi. the rest are 100 psi.

 

[Finsinthemirror]

You bet! I am not seeing anything to be concerned about. No smoke, no fluid consumption, not hard to start.. and 10 psi max difference.. that's not a radical swing deserving of concern in my mind.