400 sbc build
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350 rods are 5.787ttop said:
400 rods are 5.565 long
Chris.o is right a 400@30 over with either rod is a 406 but useing a 5.7 rod puts less stress on cylinder wall. And is basically a stroker with more cubes then a 383. Also with the 5.7 rod you should run a small base circle cam or you run the risk of connecting rod smaking and breaking cam.
well I think I have made up my mind to run with rebuit stock heads with updated springs, retainers, etc. bore it 30 over and go with flat top pistons and i think i want to use my 400 sbc rods because I cant imagine smacking the cam that would kill me. but its not set in stone so you guys keep inputting
How do you get 15mpg with 3.73s & a th350? You had to have an egg under the pedal to get 10.0 with our last one and it had less cam. But it did have a fuel slobbering Holley. Still with a tuned Q-jet I think it would have been lucky to get 12.0. It was not near as quick either. Not calling you a BSer just saying as it might be an unrealistic expectation for the OP.
Call me what you want and believe what you want. I drove that car everyday for 4yrs made probably 200 12 second passes cruised at 80mph on the highway at and yes got 15 mpg not saying everytime i drove it i am talking taking it easy And driving pretty calm. If i drove it like n ******* i would be lucky to get 10.0. O and that was with a holley 700 dbl pumper.dogshit said:
I don't doubt it a bit. The 400 in my El Camino will get 20mpg. Granted, it was built to produce max torque at cruise RPM instead of peak horsepower. It behaves more like a diesel in many ways. Specs: .060" (I know 
), completely stock rotating assy, completely stock 882 heads, Comp XE256H cam, Performer intake, HEI, Q-jet from '77 Cadillac 425, small headers, MY6 transmission with .67(?) overdrive, 3.08 gears. Cruises the freeway at 2200 RPM. It's a great driver/tow combo but I wouldn't call it a performance engine.
), completely stock rotating assy, completely stock 882 heads, Comp XE256H cam, Performer intake, HEI, Q-jet from '77 Cadillac 425, small headers, MY6 transmission with .67(?) overdrive, 3.08 gears. Cruises the freeway at 2200 RPM. It's a great driver/tow combo but I wouldn't call it a performance engine.DRIVEN, That makes sense & is 100% believable. 2480, I am not going to call you any names. I don't have any disrespect for you in fact I appreciate and agree with almost everything I have ever seen you post. Much of it obviously came from experience, helps the OP, and is not general knowledge. Just saying something probably isn't right in that mileage figure. I don't question the 12 second passes at all. Useing Wallace racing's calculators and common 26" tire 80 mph would be 3,900 rpms over 4,000 with normal converter slip. (Unless it was a lock up converter.) I wouldn't want to cruise their but sure. On the mileage I would have to see it to believe it with that gear, trans, & cam. But I don't know maybe a tight converter tall tires and a lean carb or an anomaly. At any rate its all good and I apologize if I came off insultingly as I didn't intend to.
No its cool no disrespect taken. It had 28" tires a 2800 stall that was so tight i would think it was stock. Car at 80 for some reason never had rpms any where nere 3900 if i remember it was more like 32-3300 But again i seen so i believe it if the other way around i would probably be in your shoes.dogshit said:
can I run a 406 on regular pump gas. I havent made a concrete descision because I want the 406 but this will turn into a expensive build if I go this way. My first idea was too go with a stock rebuid with a comp 292. Will this give me a little more horsepower and I really want the cam sound! Is this possible with just a stock rebuild plus flat tops and 5.7 rods w/small base circle 292?
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