what is the redline on a 1972 250ci?
That kind of depends on what cam and valve gear the engine has, but since you didn't say anything about modifications, the redline for a stock 250 is about 4000 rpm. I say about because the engine rpm on a stock 250 is limited mostly by the breathing of the engine (or lack of it) more than by the cam or valvetrain. The stock intake and exhaust manifolds are VERY restrictive.
I used to have to shift @ high RPM 4800 in my moms (stock)73 Nova 4 dr w/a powerglide.
Reason being the rpm would drop off too much when it shifted into second.
It ran a best of 19.6 @ 65 MPH IIRC @ 3000 ft track.
It did not slow down any,, even when I had my 5 friends piled in the car & raced it.
When I raced my orginal 250/pg in my nova year ago I was shifting at 4300 and it was bone stock. Went 18.50 @ 75+mph
my 250 ran mid to upper 18s with the power glide swapped to a 3speed sag. it ran low to mid 17s around 80mph stock 3:08s offey intake 600 holley & headers.other wise motor was Bone stock OTHER then a set of excel 32oz points shifting was about 5000 with the 3speed.I'd have to dig out my Old time slips to know for sure the mph
It will be interesting to see what mine runs now with this new 250, 500cfm 2bbl, intake, and exhaust. Also now with 3.70's and a 200-r4. Im hoping for 16's with the stock long block. And maybe low 15's with the hairdryer
the engine stock other than a 4 inch air cleaner I ussualy shift at about 2500 rpm
also what should my mpg be i only get about 10 or 11 mpg with a 1bbl rochester is that good or bad
That is pretty bad MPG.
Is that city driving?
My moms stock 73 4 dr Nova got 19 MPG on the freeway.
If you put the timeing where is is supposed to be it would get worse, like 16 on the highway.
I had advanced the timeing to get the better MPG.
MBHD
my '69 Nova (completely stock) w/ 250, PG, and 2.73 rear, rear went 18.8 @ 73mph in the quarter. shifted best around 4400 rpm.... otherwise it fell flat on its face. didn't really come alive til ya hit 40 in 1st. wasn't great in the quarter, but it was capable of 119mph given a long straight and no cops. Also managed 25mpg on the hwy. it regularly traversed the 280 miles between home and WAZZU during my 2 years there, fully loaded with my stuff and several passengers with no change in mileage.
I ran my '64 Pontiac Tempest down the track a few times, ran 20-flat at just a tick under 70 mph in the 1/4 mile. Still had the original 140HP 215-inch straight six (same as a Chevy six except for cubic inch size, 3.75 bore X 3.25 stroke), 2-speed Super-Turbine 300 (same 1.76 low gear as most Powerglides) and 2.56 rear end with 205/75-14 tires.
It never got out of low gear at the track, I shifted in to high gear right at the finish line. This calculates to 4060 RPM if you don't take converter slippage into account, should be a few hundred RPM above that in actuality. These engines in bone-stock form are usually all done by 4400 RPM.
The 215 was kept in a decent state of tune, but could have been better. Always retuned an average of 20 MPG in mostly 75-80 MPH freeway commuting.