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73-87 Chevy _ GMC Trucks => Performance => Topic started by: 78longbed4x4 on June 29, 2014, 04:14:26 pm
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Ok guys I just bought an 83 shortbed 4x4 with a 4 speed manual. The motor is a 454 with 781 oval port heads. I was wondering which cam and intake would work best for this truck. It's lifted 4 inches with 38in swampers and it's gonna be basically a toy for me to just cruise around and do a little muddin with, not gonna be a daily driver. Any ideas? What carb will work best? I have a brand new 670 Holley on my 78 Chevy and I'd like to use it on the 454 but I'm not sure it will be enough cfm for it.
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for cruising and a little muddin, why not leave it as is? Is there something wrong with it?
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Well the motor is outbid the truck right now. The guy I got it from pulled it and was gonna build it and he put the heads on it and then decided to go with a different project, so I figured while the motor is out of the truck I might as well freshen it up and add some goodies before I stick it back in
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I'm thinking if you aren't going to tow regularly with 454 cubes, and a 4sp, you can get away with a little bigger than most. The 781s flow like the Mississippi River, so good start there. I recommend a hydraulic roller, something in the 280 advertised duration range. And a Performer RPM intake. Top it off with a 750 Holley vacuum secondary carb, and you'll run out of money buying u-joints, and tires.
I have a 454 with 049s (same as 781s just different year). I have a solid cam, and a Holley Strip Dominator intake. 750 Holley carb. Even with my "high RPM" build the 454 (actual 461) gives me enough torque to baste the back tires at will. I also cut in 2.19in/1.88ex valves and pocket ported the heads. I spin my engine 7,000rpm a lot.
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Would a hydraulic flat tappet work just as well? I've looked into a roller cam but the lifters are expensive
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I run a solid flat tappet. Good performance. Just be prepared to adjust the valves a lot. Like every 3,000~5,000mi.
The problem with a hydraulic flat tappet is in order to get enough lift to let those 781s to breathe you will need so much cam duration that you will lose out on the low end grunt that makes a big block fun to drive.
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So if I went with a solid flat tappet and maybe throw some roller rockers on and headers with an rpm intake would it run good with my 670 Holley or would I need a bigger carb? I would hate to get rid of my carb cuz it's brand new almost, I'm just afraid it won't be enough to keep that big block fed
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IMHO, I don't think "too small" exists with carburetion......within reason.
The 670 will run fine on any 454, but it will limit your 454's output.
I have a 750 vacuum secondary carb on my 454. I could go bigger but it may cost me on the low end making town driving suffer.
Since you have the 670 already you could try it first, and go bigger later.