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1978 460 added parts now im slower???

2K views 15 replies 9 participants last post by  sandguy356 
#1 · (Edited)
I have 1978 460 I use for mud racing. Last year it was completely stock and I could rev and was faster then I am this year. Over the winter I put in a cam, lifters, rods, heads, aluminum intake, bigger fuel pump, 3500 stall. I am not revving no where near I was last year and am slower by 2 to 3 seconds. Any clue what it could be? You would think with those parts I put in I should of been a little bit faster.
 
#4 ·
With all that you've added, have you done anything with timing, carburation, or exhaust flow? Adding better parts doesn't do shit if it hinders the engine on any of those 3 aspects. You've improved air intake incrementally, but without additional fuel/air flow and mix, and timing to support it, and exhaust to get rid of it, you create the situation exactly where you are at now, loss of power.
 
#8 · (Edited)
Not to be a Dick, but poorly ported heads can actually reduce performance significantly. Does the guy that ported the heads have a clue what he's doing, and access to a flow bench, or did he just grind metal away until they were "ported and polished". Big block fords have some of the biggest Ports available in factory heads and someone porting heads can easily and quickly ruin them.

Point being, ask if the dude flow bench tested them for actual air flow gain (with real data to back it up), or if he just "ported" them. If he just "ported" them, I would swap to your original heads and see what happens with the other upgraded parts.
 
#7 ·
Hmmm. Did you degree the cam? google 460 timing chain marks and you will probably learn a lot. Carb choice has a lot to do with things as well. Have the heads been ported an polished? Those can get screwed up in a hurry if the wrong things are done to them.
Distributor could be 180 degrees off, but I'm not sure that those motors will even run that way.
I'm running a smaller cam than you listed and mine idles above 1000 RPM just to stay running and I'm pushing 35 degrees timing. That will probably get backed off a touch as the rings seat and compression is increased, but that's 1 more thing for you to check.
 
#9 ·
You're also taking your buddies word that they are matched, and have a undesirable end result. Don't take his word until the facts are proven.
 
#11 ·
A failure to get an engine to "rev" has nothing to do with the stall converter. Does it rev in park?

Sounds like your buddy had an issue and he sold it to you!! Same parts, same issue, something was and still is wrong with the carb, cam, intake and head combo.
 
#15 ·
I would suggest tearing down the engine, take heads to a machine shop or somewhere with a flow bench. Get your flow rate specs to see where you stand. Then i would get a hold of an engineer at comp cams or howards, even an engine builder. Give them all the specs of all of your engine components and see what they suggest. Most are happy to tell you where you went wrong and what you can do to fix it. Also, are you making peak power at 3500 rpms? If not, a 3500 stall isn't going to help you in anyway.
 
#16 ·
What heads are they? Factory or something aftermarket?
If they are D3 factory, even an unported DOVE set will be better than all but the best ported D3s.
If the heads flow anything decent, you'll find that 750 is too small, BBFs like more cfm when you get a good slowing set of heads paired up with a good intake.
 
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