Decided to rebuild my 304.

[bkjolly]

I've looked for a 401 or 360 around here for the better part of the winter. The best I can come up with is a running 304 in louisville to throw in there while I rebuild the Jeep's original engine. I'd like some input on which way to go with this. I can get the master rebuild kit with the RV cam and order the intake and carb seperate. But my question is does the Edelbrock cam make that big of a difference? Also What other modifications should I make? I'm not looking for anything spectacular just 200-250 horsepower and around 300 ft-lbs of torque.

[dwg86]

Just some info about piston selection for a 304. I built a 304 years ago and wanted to raise the compression without paying big $ for custom pistons. I talked with my machinist and we started looking at different pistons. I ended up using 199 amc 6 cylinder pistons ($13.00 each). The bore and comp height was the same. The top of pistons were plenty thick enough to notch for the valves (I think he charged me 100 bucks to notch). The machinist cut one big valve relief for both valves. I used a comp cams 280H cam 490 lift 230 dur @ .050 (a bit big for 4 wheeling). That little 304 would scream! Beat a few mustang 302's in my cj5. Don't know what the final static comp ratio was (i never cc the piston and heads). Heads were late model 58cc. I'm sure the comp ratio was pretty high because the pistons were flat tops but I never had detonation problems. It could be becuase the valve overlap of the cam was pretty big.

[dwg86]

Also you might want to check www.car-parts.com for engines. Its a junkyard search page.For instance search jeep wagoneer 401 engine. It will give price, location and condition of all 401's in junkyards that are listed in the system.

[Goose]

Hmmm I tried it and al it would search for was the 360 or 258

[dwg86]

TRY YEAR 1976. IT SHOULD GIVE YOU A SELECTION OF 401 CODE Z

[bkjolly]

Thanks for all the info guys. The piston info is great. Any idea what the compression was increased to? As for the performer intake and Clevite cam combo does anyone have any input.

[dwg86]

info from advance auto parts web site.
304 PISTON P/N 1079p30 - sealed power cast piston, 8.4:1 comp ratio; 3.750 bore .030 over; (2) 5/64 (1) 3/16 ring groves; 1.581 compression distance; recessed head .130 deep x 3.320 diameter
258 PISTON p/n 409p30 - sealed power cast piston 8.0:1 comp ratio; 3.750 bore .030 over; 2) 5/64 (1) 3/16 ring groves; 1.581 compression distance; recessed head .108 deep 3.125 diameter
So it looks like you could use a 258 piston in a 304 and bump up the compresson. Same bore size and comperssion distance (distance from center of piston pin to the top of the piston) . The 304 piston is dished more by .022 and the dish diameter is bigger by .195 .I am assumming the 304 piston has 4 valve reliefs and the 258 has none (don't need valve reliefs on an inline 6 cylinder piston). You could use the 304 piston as a template and only cut 2 valve reliefs the same diameter and depth as the 304 piston...not hard for a machine shop to do. What do you think guys?

[bkjolly]

I think your a genius. I would love to have a great 304 and forget building a bigger engine I'd like to keep the heart of the Jeep original just beef it up and make it pretty. Any idea where to get AMC blue high temp paint?

[jeepsr4ever]

seymour paints part # en-66

[dbesade]

I think your a genius. I would love to have a great 304 and forget building a bigger engine I'd like to keep the heart of the Jeep original just beef it up and make it pretty. Any idea where to get AMC blue high temp paint?

totally agree.. unfortunately.. my Cj is a DD.. and my 304 is starting to show some signs of rebuild time.. so I have a 360 on the stand getting ready for a rebuild..

-Dave