Big Block hopes........
Thread Starter
Staging Lane
Joined: Jan 2005
Posts: 54
Likes: 0
From: JOLIET,ILL
Big Block hopes........ Can anyone give me a rough est. on a H.P. output on a Big Block Chevy motor. The block is a 1978 (truck) stock heads not sure of valve size(2.19-1.60 i think?) cam is 500'' int. .218 dur. 500'' ext..228dur. 8.5to1 comp. intake is an Edelbrock EFI performer RPM kit. I would like some ideas to get more HP i was thinking a bigger cam but not sure what size or how big i can go with the heads i have.. and dont have money for new heads till next year... any ideas would be cool Thanks.
7 Second Club
iTrader: (5)
Joined: Nov 2001
Posts: 8,834
Likes: 1
From: Gainesville, Florida # of drag strips runs: ?!?!?
the stock heads (provided they are 1978 vintage) will be your crutch until you get a better set. The old "weakest link" rule applies here, as better cam, intake, carb and such only helps so much if you can't get the heads to flow what you want.
Derek
Derek
Baltimore Whore
iTrader: (95)
Joined: Apr 2004
Posts: 16,776
Likes: 0
From: In a van DOWN BY THE RIVER
probably around 265 285ish.Need a better set of heads and bigger cam to let the motor breathe.Get the heads milled a bit bigger valves and a good valve job.That will help out a good bit untill you save money for new ones
Those stock heads are probably the oval port 781 casting. They do not have 2.19 int, 1.88 stock sized valves. But with a decent port job, mainly on the exhaust side and 2.19/1.88 valves, those heads will support 500 hp on a 454 with a decent hydraulic cam. You can really wake them up with pocket porting on the exhaust side, the bigger valves, and milling for more compression. They're really pretty decent for an OEM head. The big block heads that are the real bad ones are the "peanut port" style on the 86-94 big blocks. Those aren't even worth porting.
That cam you have is the same duration as the Edelbrock 2162 cam that also comes with the Performer (not rpm) intake if you buy them as a combo. I wouldn't go bigger unless you at least mill the heads for more compression. A bigger cam will just bleed off compression.
Jason
That cam you have is the same duration as the Edelbrock 2162 cam that also comes with the Performer (not rpm) intake if you buy them as a combo. I wouldn't go bigger unless you at least mill the heads for more compression. A bigger cam will just bleed off compression.
Jason
the low compression and heads is hurting you for sure.if you want alot of extra power spray it.if you plan on mods later,especially heads,i would rebuild the motor and put slightly bigger domes in and get a bigger cam.just remember what cr you have when you get another set of heads.
