Ok, what was so different with the 1970 350 that gave it 410 lb/ft of torque at 3200 rpm. That was only 100 lb/ft less than the 455 which produced 510 lb/ft at 2800 rpm. Also the hp rating was a healthy 315 hp. This seems like it would really move a GS or Skylark along. Does any one know what the cam profile, spring rate, and rocker ratio numbers are? I would love to know. Thanks.
Jason, 100 ft lbs. of torque is alot of difference. The 70 SP 350 was rated at 10.25:1 compression. The other 350's had 9.0:1 or less. The other differences probably had to do with carb metering and ignition curve. I don't think there was any difference in the cams The GS had the ram air intake. We all know it didn't work very well, but it looked cool. The factory had to show a power increase for the GS. It's all a ratings game. Just like the 455 in the Rivis was rated at 370 HP while the Stage1 GS had 360 HP.
Jason The 70 350 motor ( SP) which was found in the GS cars and special ordered in the Skylark's...came with 10.25 compression ratio...which was more then 2 of the 3 455's motors built that year..only the stage 1 motor ( SS ) had more compression 10.50..which would give most of the reason for the high torque rating...I don't know the stock cam profile..but the spring rate was 75lbs closed and 180lbs opened..and rocker ratio was 1.55 to 1...the 350 motor was made in 2 other version's and only had 9.0 compression ratio's...AND our 350's were lighter!!
How about the difference in specs between the 70 and 69 350s. I've got the original 350 4bbl in my 69 GS California. it was rated at 280 HP and 375 ft.lbs ot torque. What changed in 1970 to get more power? Is there a weight difference? The compression on the 69 was also 10.25:1. Cam difference?
Thanks for all the replies every one. Larry are you saying that the 70 350 really didn't have the horse power and torque ratings that buick gave it? I was under the impression that if any thing buick under rated all of thier engine performance specs. Also Larry is there any where in print that you or any one for that matter knows of that would tell us what the ignition curve was? Is there any difference in deck hight for 1970 or is the only difference in compression due to taller pistons? If any one knows the answers to these questions feel free to answer. Thanks
Jason, I'm not saying the figures were fudged by Buick. That was a potent engine. But in 1968 and 69, the identical engine made 280 HP and 375 lb-ft. Maybe they figured the ram air system was worth that much more. I believe the deck height would be the same within factory tolerances. As far as the stock spark curve, this is what the 70 Chassis manual says. We can do better than that(more initial and advance in faster)
Awww Fudge Given the dyno results of my new 350 which utilizes all Buick pieces (modified to some degree), I seriously doubt the 410 TQ number referenced.:error:
365 peak horse 400 peak TQ All around 5800 RPM I will say my final compression was just south of 9.9:1. However, my heads had a lot of work done to them and the manifolds were ported. I used a bone stock intake, JO 750 QJET, and Dave Small Body HEI.
Dave - Sounds like a great combo!!:TU: :bglasses: Did you go with the oversize valves? Which cam too? Thanks.
