Thread: 350 SB stock torque rating

Tweet

Well you may not like this but here is the data from the 1982 Chilton's Auto Repair Manual for Chevelle 350 V8 w 2 bbl:

Year HP@rpm Torque@rpm(ft. lb.)
1975 145@3800 250@2200
'76-'77 145@3800 250@2200

'78-'79 170@3800 270@2400 350 V8 w 4 bbl

Corvette w 4 bbl (from Chilton's 1963-1982 Repair Manual)
1969 300@4800 380@3200
1970 300@4800 380@3200
1971 270@4800 360@3200
1972 200@4400 300@2800
1973 190@4400 270@2800
1974 195@4400 275@2800
'75-'76* 165@3800 255@2400
1977 180@4000 270@2400
1978 185@4000 280@2400
1979 195@4000 285@3200
1980 180@4200 255@2000
1981 190@4200 280@1600
1982 200@4200 285@2800 (TBI)

In each case I have listed the LOWEST rating for a 350 V8; there were of course high performance optional engines closer to 350 HP. There are two main effects here. First around 1971 GM changed the way it reported H.P. from flywheel w/o accessories to with accessories so that lowering is somewhat artificial. The second factor is more serious in that the Corvettes were detuned for the gasoline embargo experienced in 1974 for a few years. I have put an * at 1976 because I bought a '76 Corvette (2-bolt) thinking it would be higher performance from a Corvette only to learn that was the lowest H.P. Corvette! Still with a cam similar to that in the 300 H.P. 327, flat top pistons giving a C.R. of about 9.2:1 with shaved 882 heads, headers, and an Edelbrock Performer manifold I hope to get at least 250 real H.P. and with 1.6 ratio rockers on the exhaust valves I hope to get about 370 ft. lb. or more in torque at low rpm, but who knows until I get it to a dyno, if ever. Maybe you should invest in a Chilton's Repair Manual, it has a lot of this sort of stuff in it.


If you want some encouragement take a look at Ryan's Dyno site:

http://www.ryanscarpage.50megs.com/combos1.html

With a small cam or just a stock cam it looks like 1.6 ratio rockers on the EXHAUST valves can really improve torque, I hope so!

This exercise has been partly for my own understanding in relating to my frozen brain memories of flathead Ford V8s:

'42-'48 95@3500 HP@rpm 177@1700 ft. lb. @rpm stock
'42-'48 112@3600 HP@rpm 200@2100 ft. lb. @rpm modified

These values are taken from a graph given in the Speed and Power Handbook, Newhouse Automotive Industries, 1952, p56 and the modified data for the flathead is for just higher C.R. of 8.5:1 and dual Stromberg carbs. The actual data from Ford may be slightly different, but you can see that even a stock SBC 350 is far more powerful than a slightly modified flathead common on the street in the 1950s and any rodder with 8.5 heads and a dual intake in 1955 would have thought it was souped up to about 3/4 race, so the Corvette 165 H.P. motor looks pretty good to me and 250 H.P. should be great for a retired guy like me!

Don Shillady
Retired Scientist/teen rodder