Chevy Impala SS Forum banner

1 - 11 of 11 Posts
K

·
Guest
Joined
·
0 Posts
Discussion Starter #1
I'm getting a LT1 engine out of a 9C1 to put in my jeep and was wondering if someone could tell me the RPM's at highway speeds (60mph). I need this info so I can figure out my gearing. I'm also buying a 95 9C1 to replace my old import racer.
Thanks
 
P

·
Guest
Joined
·
0 Posts
Discussion Starter #2
Ken,
I think you got the cart before the horse. If you know what gears you have in the jeep, you can figure out what the engine rpm will be. If you are actually inquiring about the tranny gears that was with the LT1, fourth gear is a .7 overdrive, that is the driveshaft will turn at 70% of whatever the crankshaft speed is.

Hope this is what you needed.
 
K

·
Guest
Joined
·
0 Posts
Discussion Starter #3
I'm looking to find out what the factory rpm's for the engine were at highway speeds(60mph). I don't have the engine in yet and I know what gears I have. I just need to fiuge out what gears to get. I'm putting 38" tires on the jeep with new diff's and don't want the engine running near redline or have no get up because the ring and pinion gearing is to high or to low.
 
K

·
Guest
Joined
·
0 Posts
Discussion Starter #5
I like the calculator that will make the figuring easier, but the rpm ranges they give are pretty large(1000 rpm). I was wandering if anyone could get me a little closer or narrow the range down.
Thanks
 
P

·
Guest
Joined
·
0 Posts
Discussion Starter #6
try here, It does'nt have 60 or 70 mph, but it breaks in down by 500 rpm differences, using 3.08,3.42, and 3.73 gears.
 
9

·
Guest
Joined
·
0 Posts
Discussion Starter #7
At 60, it's turning right around 2000 rpm. The LT1 will cruise comfortably up to 2500 or 2600 rpm. After that, the gas mileage will start to fall rapidly. 2800 is the upper cruising rpm of a SBC. I think the 2000 is actually to slow, and kinda lugs the engine. If I could pick the rpm for my engine at any given cruising speed I would be driving, it would be 2200-2400 rpm. Is that what you were looking for?
 
R

·
Guest
Joined
·
0 Posts
Discussion Starter #8
96 Caprice with stock 2.93 gears and stock 235/70-15 tires (28" tall)
60 mph 1500rpm
70 mph 1750rpm
80 mph 2000rpm
my wife's car (96 Caprice) with the same gears but Impala wheels and tires (27" tall)
add about 100 rpms.
 
K

·
Guest
Joined
·
0 Posts
Discussion Starter #9
Thanks a lot guys those were exaclty the answers I was looking for. Got it narrowed to 4.10 or 4.56. Thanks Again.
 
W

·
Guest
Joined
·
0 Posts
Discussion Starter #10
What size tires are you planning on running? Also, let me know how the swap goes, my buddy has a 4 cylinder TJ and I've been trying to get him to put a 350 in his for a long time now. With the lift and the big tires, 5th gear is useless in his.
 
K

·
Guest
Joined
·
0 Posts
Discussion Starter #11
I'm planning on 38". I have 33" now and I had to put 4.10 gears to get my power back.
Kenneth
 
1 - 11 of 11 Posts
Top