Hey gang, My small block self destructed and I picked up a 454 (72-78 2 bolt) with 781 heads. The previous owner had it in truck and rebuilt it. 60 over, 1.7 rockers, Weiand action plus intake, Holley 750 double pumper, and a RV cam of unknown origin. I'm guessing it has around 8:1 compression. It runs good and I'd like to put it in my 55 with minimum mods to motor. The 55 is a 4spd, 12 bolt 4:11 posi. I'm not looking to race the car but I would like to spin it up over the 4500 rpm the RV cam limits it to. Would it be as simple as a cam and spring change? Would a 400 to 425hp goal be unreasonable? I'm new to the big block world and looking for some low budget ideas. Thanks, Rich Posted using the Full Custom H.A.M.B. App!
You need to change that rear end ratio. All you are going to do with a BB and that ratio is spin the tires. A buddy in high school put a BB in his 70 Chevelle with 4:56 gears and he couldn't out run anything cuz he couldn't keep the tires from spinning.
Your rear end ratio is fine. It's tuning your chassis for traction instead of just spinning. But ya, Cam and springs will wake it up. Might look into a thinner head gasket or milling the heads a bit to get compression up a little.
watching the replys here for any ideas for my 454...peanut port heads out of an RV. I dont think theres much to be done in my case but still interested to see what replys you get.
lots of big block builds in magazines. Hot rod did one on a low compression 454 in 1989, using 049 heads and a comp cams 280H that pulled 430 horsepower with an 850 holley and big valves, they said the stock valves dropped the hp by 15. Super Chevy did a 402 with peanut port heads a few years back, and easily pulled over 400 horsepower, but I don't remember the cam specs.
It's hard to beat a BBC for stupid power. Not as cheap as a 350, but nothing is. If you're wanting just to do a cam change, I'd make 1 call, Straub Technologies. Chris will custom grind a cam just for your application, compression, gearing and intended usage. http://www.straubtechnologies.com/ Aside from that, if you're willing to get into the motor a bit, BBCs respond really well to compression. Around 10:1 is good on a street iron headed BB. Aluminum heads will allow you another point or so on pump gas. Every point of compression is worth approx. 4% torque. The heads you have are decent in stock form. They can be made pretty darn good with some time and a grinder, and opened up to 2.19/1.88 valves. I've seen some as small as 113cc chambers and others as large as 121cc chambers. That Action Plus intake isn't going to do you any good with your 4.10 gearing. It's really not any better than a high perf factory intake, just in aluminum. Considering you're likely spinning 4k or so down the highway, that intake is done around 4500 also just like the cam. Maybe look into a Performer Rpm or Victor Jr. The 750 carb should be ok, but an 850 double pumper would be closer to ideal for your manual transmission and gearing. Devin
Just make sure you read up on how to set the valve lash on a BBC. Would hate to see this one "self destruct" too Posted using the Full Custom H.A.M.B. App!
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