View Full Version : new amc guy.dumb question 304 build

do it again
05-17-2005, 09:50 PM
i have a stock 304 in my 74 javelin.im going to build it. i think i want 300 horse.i want to keep most everything else near stock.suggest? would a performer intake and 4 bbl with a hot cam and 030. bore job do it or do i need a 360?also my jav has a t-15 3 speed.

Big Bad AMX
05-17-2005, 10:10 PM
You'll need more than a cam, intake and .030 to get 300 horse out of a 304. You're better off starting with a 360 or a 401 though you'll want to swap to a 4-speed too, the 3-speed likely won't hold up well.


05-18-2005, 11:18 AM
Hi, to get a little under 300HP out of your 304, I recomend the following.

An Offy 360 spread bore intake (non-dual port, very hard to come by... my last one cost over $270.00). Or you can use another hard to find AMC cast intake for 74-76 401 (Jeep).

An 1 inch spread bore spacer with separate venturi holes (non-open type).

Holley 650CFM spread bore carb. (double pump is over kill but can be done right by going with small shooters).

Half length dual exhaust 2" (you dont need large pipes).

Headers if possible, or get your exhaust manifolds ported and shaped by a pro.

Cam... no need for a race cam just get a good torq producer at mid range to 6000 RPM.

New valve springs, retainers and locks... OEM or stock replacements are not good enough. Don't go too high on spring pressure.

I used to drive my 304 on the Freeway on ramps in first gear at 55 MPH for years and cruise at 145 MPH with stock valve springs... I could have got more top end with performance springs and retainers.

The reason I am pushing this type of setup is that it is tryed and true with my 73 304 I had in the past.

The theory behind this is from Buick... The nail head 401 and 425 engines from the early and mid 60's were very powerfull. They had the capablilty to move a 5,000 lbs car into the 15 second quarter mile in stock form. Funny thing is that they had very small diameter valves like the AMC 304. By moving the torq range within driveable RPM range you can achieve greater HP without the need for high RPM. Plus you don't need 4.11 gears to do it.

I think the highest Buick ever used with a nail head was 3.55 gear and that was on the 65 GS.