pop ups or not

ragtop19sixty9 · 03-30-2007, 05:51 AM

Morning all. Just need alittle advise

. Have a 69 stingray,and it has 350/350 with 11/1 pop ups pistons. I'm going threw the motor and have had some friends said i sould take out the popups

and put others in because of the gas problams I might have when its finished. I dont want to

,but any ideas...have a great day all.....

.....thanks Philip

**Rich Z** · 03-30-2007, 12:15 PM

Well the higher the compression ratio, the higher the octane rating your will need on your gasoline. That was all well and good when we had leaded gas (lead was a knock inhibitor) and 102 octane at the pump, but those days are gone. I don't think I would go more than 10.5:1 myself, especially with the ready availability of FI systems these days.

Of course, that being said, seems to me I read somewhere that the compression ration on the LS2 is 10.9:1.........

06c6corvette · 03-30-2007, 01:26 PM

Keep the pop ups you shouldent be over 12 to 1 which is just a little higher than the LS-2.more compresson makes higher HP.Good luck with the re build.
Mike

85vette · 03-30-2007, 04:51 PM

Quote:

Originally Posted by Rich Z

Well the higher the compression ratio, the higher the octane rating your will need on your gasoline. That was all well and good when we had leaded gas (lead was a knock inhibitor) and 102 octane at the pump, but those days are gone. I don't think I would go more than 10.5:1 myself, especially with the ready availability of FI systems these days.

Of course, that being said, seems to me I read somewhere that the compression ration on the LS2 is 10.9:1.........

Been there, done that. Myself, I would drop the compression. I had a 12:1 383 stroked LT1 in my 71 Z28 and it just got to where it wasn't fun to drive on the street. The newer design motors can get by with the higher compression ratios due to the reverse flow cooling systems, but I was runnin Cam2 fuel and running hot at red lights. It got old. I enjoyed my 78 Z28 with a lower compression 454. It was much more streetable, used pump gas, and still made 450 HP with 10:1 compression. The 71 was better suited for the 1/4 mile track.