CJBilly
Hey guys- long time reader, first time poster. :?
What are the "pro's" and "con's" of installing these heads on a 304? Any major issues that someone would need to deal with?
Thanks!!!
jeepsr4ever
Yes the 304 block is tapped with 1/2-13 bolts and the 343 heads have 7/16" holes. Other than that the flow isnt as good as a set of stock 304 heads believe it or not.
CJBilly
Ummmm- #-o
The last time I looked at a 343 spec sheet, a 343 put out some pretty good HP. Maybe this was due to the compression available from the heads? That along with the slightly larger cu.in. heads would allow the 304 to breath a little better.
Are the heads good for anything besides boat anchors???? :roll:
Thanks for your comments...
jeepsr4ever
Sure! Those looking to restore and ebay.
76-cj7
By any chance would you have the rest of the motor to go with the heads?
gschuld
to 76-CJ7
Do you need a 343 or are you just curious. I have a running 343 that was just pulled from an AMX. I got it in trade for a nice running jeep 258 that a friend wanted from me all of a sudden. He apparently puked a rod in the 258 in his Cj7.
And in regards to the 343 heads on a 304 thing, the dogleg exhaust design on the 304 heads are a good bit better than the 343 rectangle port heads' exhaust. Basically the only potential advantage of 343 heads over the 304s would be in the larger valves they run. The problem is the valves of the big valve heads would actually hit the cylinder walls of the small bore 304 motor. Some creative clearancing at least would be necessary to make them work if it is possible at all. Regardless, unless the 304 in question has some pretty significant performance improvements in the rest of the intake/exhaust track, the stock valves are not likely to be much of a bottleneck in the flow department. I'd bet a basic pocket porting and minor back cutting of the stock valves along with a good 3 angle valve job on the stock 304 heads would make a nice improvement. A step up from there would be going to a slightly larger set of valves but not large enough to cause wall clearence problems. I've got an extra set of late 70's 304 heads laying around if you want to try your hand at rebuilding/porting a set without having to pull your heads and deal with the down time.
Hope this help,
George
AMX69PHATTY
All AMC 290-304-343-360-390-401 V-8 motors interchange.
That 343 can easily be made into a 360.
The AMC 304 & 360 use the same 3.44 Crank.
The AMC 290 & 343 use the same 3.28 Crank.
The 290 & 304 have the same bore.
The 343 & 360 have the same bore.
The 290, 304, 343, & 360 all use the same Rods.
The 343 block has a .033 shorter deck height than the 360.
That makes it easier to get better compression.
304/360 crank, 343 block, new 1.58 CH cast dished pistons
gives a good CR and the all important .000 deck clear and .045 quench.
The 304 Heads are better than the 343 and can be cut for larger valves.
Start with the 343 block, assemble with a 304/360 crank, bolts right in,
and that crank fits right up to your TF999 transmisson.
You could use the crank out of your 304 or get another.
Could sell the 343 crank & heads on ebay or hold on to'em.
Have the 304 heads worked over and put them on the 343 block.
The smaller 304 Valves will imporove low end torque.
Then you'd have a 360 CI motor, good CR, and good Dog Leg heads.
All this could be done with parts that you already have.
This is the motor combination I have ran for 10+ years.
just my .02
