optimal freeway RPM's for a small block chevy??

that's an old thread! 2008....

I bet we get a bunch of answers to the 9 year old question.

Yeah, that's how it is. In the old days, the engine sang a sweet tune on the highway. Now we want them to be quiet and get good gas mileage.

 

Your truck also had a knock sensor. Low rpm cruse speeds may not work well with todays fuel.

 

damn. 9 years and the car in question still is not on the road. I may solve my 3.08 /overdive problem by not using the 305 and 700R and instead use a 400 SBC and a turbo 400

 

I have a 350/TH400/GV in my suburban, with 3.08 gears. gets decent mileage.

 

Exactly Jim! This is what I need to constantly remind myself of when I want to bail on my y-block/flat-o-matic/C-4 combo.

 

My DD in a 97 chevy 2dr 2wd stepside 1500. Factory 5.7 vortec 29" tires 3.42 rear gears New Venture 5sp and around 2050 RPM at 70mph. 17mpg highway 15 town with no-ethanol gas. 1.5mpg less with E10.

 

with a o/d I find around 1850-2100 @ 60 is a good number for a small block , a little higher if its a 305 or smaller , try to keep it in the base of the torque curve if possible above 160-180 ft lbs ,

 

Newer cars with nverdrive have lowered our tolerance for rpms. I ran my old 66 c10 with 3.73s for years at 3000 to 3400 rpms all day long with no ill effects other than a best of 12 mpg, which comes in comparable to any od truck Ive run. I would run hardened seats on any combo spinning this high now.

 

This is what my 355 SBC runs at, with the cam and heads it wants to run like that and I like it, plenty of punch at 60 if I need it. Really nice to drive around town, the rear is a 3.89 and I had a 3.56 in it... lug city at 30 or 40.

 

@jhutch - Did I miss the memo where we were supposed to bump 9 year old threads?

 

Ha! I didn't even notice. I don't recall doing a search for but I guess that's what I did. In any case, 9 years old, 19 years old, 39 years old... I have the problem today!

An it's kinda funny that 49ratfink still doesn't have it on the road! Good stuff.

 

I've had the car for 40 years, I am in no hurry.

 

I understand. I'm going on 14 years with this 1963 Vespa I have. Some day it will run under it's own power!

 

with over 20,000 posts I think she is just letting the rest of us catch up.

 

350, small cam, 410 gears 32 inch tires, 400 trans
loves 2500-2800 rpm
that's in the 60-70 mph range
plan on going OD when the cash flow is right

and it weighs 6500+

 

I built my 26 T coupe with a 350/700R4 with a Maverick rear w/2.79 gears w/ 28" rear tires, with full intentions of changing the rear gears to 3.5-3.7 area. I have now driven it with the 2.79's for 12K+ miles. I kind of like it like that. I always drive it in third gear (1:1) around town. The 2.79's kind of mitigate the very low 1st gear of the 700. 55 mph in 3rd is about is about 2300. Put it in OD and 55 is about 1600. 70 mph in OD is 2000 rpm. I like shifting the gears. Would have a 4 speed if my old knee would stand it.

 

I have a 55 chevy that has the pg geared 3.55's, used a 200R with unknown stock 400 HEI, quadrajet. I run 70 at 2100 rpm. Car is great cruiser I get a steady 17mpg. I once got 20 with non ethanol heading to dallas. It seems every 400 motor I had got 1.5-2mpg less they are just pigs. I'm sure with a 350 it would 19 average. I am looking a tri 5 wagon and will run a 327 or 283, M20(wide ratio) with probably a 3.36 gear.
My experience is 283/327 like a little more rpm so trying to keep it at 2900rpm or less.

 

Look at late model V8's with all the controls, fuel inj, overdrive etc. Factory sets them up to run 1800-2200 at highway speed. I consider that the sweet spot. Granted fuel inj will allow good control at lower rpm that we may not be able to achieve without very good tuning skills.

If you can cam and gear your car to run there and do everything else you want, youre in good shape. Tune it well. Theres always trade offs in any build though.

 

Now it's 10 years old
9 yrs, 11 months and 1 day but who's counting.

 

I know this old but the thought of a SBC without stating cubic inches is baffling to me even back when this was started. I'm ***uming 350 is the norm but when trying to figure out rpm when it could be as small as 262" and big as 422" or bigger which what mine would be doesn't make sense.... Oh well.

 

Oh well??
Need the cubic inches do you ??
Found in the First post. You could try looking there or expand 49's quote below. 10 years go by and nothing changes here.

 

Every calculator a guy could ever want is right here:
http://wallaceracing.com/Calculators.htm

 

I'm planning a 283 with a mild cam, 3.08 rear gear and a 25.5" tire. I was advised to go with a TH350 in place of a 2004R to keep the little smallblock at around 2600-2700 rpm's at 65mph. Any thoughts???

 

If you have a 200-4R arlready, then maybe going to a 3.55 or 3.73 gear would be a better way to go? If you have the TH350 and the 3.08 gears already, it will probably work out ok. Kind of depends on what kind of driving you're really going to end up doing with the car.

 

wifes 55 has peppy 327 with 700R trans and 3:42 12 bolt with posi--seems about right-her old 95 SS had a 700R with 3:42's and was a fantastic high speed road car.

 

this thread is 11 years old.

 

yeah, but the new question tacked on the end is only a few hours old.

 

Did you get this car running?

 

I went old school all the way, my 36 has a 64 327, 30 over, flat top pistons, turbo 350, and lately a ford 8.8, which came with 355's, but because I took a 273 10 bolt out of it, the engine felt like it was coming through the floor of the truck, with the 355's. Promptly installed 275's in it, back to the perfect combo for me. Cruises at 2000ish all day long, wanna p*** 16 cars, poke it hard, downshift to second, pulls like a madman till 85 miles an hour till 3rd happens again. Everywhere I go is hiway work, low rpm's are the most soothing, she just hums along, but will do what I ask her to when needed. Truck is only 2700 lbs. I should add, its still a good race for a 5 litre mustang, so the old girl is fast enough for me, BUT, my duramax will challenge my 36......

 

X2 --- I have near identical set up in my 32 sedan 350,t5, 3.00 8"rear and 255 rear tires. Runs about 2100 at 75 mph.