amc 360 rebuild tips

daves1985

Can I put 343 Pistons .060 in my 360 also will the master rebuild kit work from a 343 to a 360

AMX69PHATTY

user PaintedRat did it in February 2007

see his thread about it here:

http://www.bulltear.com/forums/viewtopic.php?t=6620&highlight=360

Understanding is everything from the 343 kit fits a 360.

360 vs. 343 differences:

Dogleg Exhaust Port vs. Rectangular Exhaust Port
57.92cc vs. 50.60cc nominal, exception 360 prior to mid '71
Bridged Rockers vs. Stud mounted, exception '73 & older
1/2" dia head bolts vs. 7/16" dia head bolts
9.208 Deck Ht vs. 9.175
.012 deck clearance vs. .060
_26cc dish, .21 deep reliefs vs. _4cc 2V, _14cc 4V, ~.16 deep
3.44 stroke vs. 3.28 stroke
Crank Flange '72 & up for TorqueFlite vs. Borg Warner
Tall H20 pump & Pulleys, 4 bolt Dampener vs. Short & 3 Bolt '72 and earlier
Angled Oil Pump Cover Filter Adapter vs. 90 deg early design
7.820 Pushrods vs. 7.767, due to .033 taller deck, exception 7.800 in '70 & '71]
(2) center Intake Bolt locations higher/wider vs. In-Line
Slightly wider Intake vs. slightly narrower, .033 per side (deck ht)
10:1 4V, 9:1 2V '70, 8.5:1 4V & 2V vs. 10.2:1 4V & 9.0:1 2V
1.680 dia exhaust valve late '70 & up vs. 1.625

Otherwise, pretty sure everything else is the same and interchangeable.

Stock 360 has 1.600 compression height same as stock 343.
Badger, TRW, Sealed Power slugs are 1.580 Comp. Ht.
Understanding is Egge slugs have 1.570 Comp. Ht.
Egge 343 slugs should have .042 nominal deck clearance.
If rods are re-conditioned and .003 shorter, .045 deck clearance.

In PaintedRat's thread, a mention of a slight counterweight clearance mod to the egge slugs.

Wrench Man

My 360 has 343 pistons in it, the 360 has dished pistons, 30cc's??, the 343 pistons are flat tops with vale reliefs, expect MASSIVE! gains in compression instantly!!!!, if I remember it's about 13:1 with "291" heads! (@.060 over)

hohner0006

My 360 bored .030 over with Badger 343 pistons came out to 11/1 comp with 58 cc heads.

AMX69PHATTY

All values are Nominal, believed correct but not guranteed, have
manufacturing variations, and must be confirmed from actual parts.

Using 14cc for Egge 343 2V Pistons in an AMC 360:

Result: 9.31:1 Static CR
Offset grind crank or mill deck and/or heads more to increase the 9.31:1 CR

4.110 Bore - stock +.030
3.440 Stroke - stock nominal
9.208 Deck Ht - stock nominal
5.872 Re-Con Con Rod - 0.003 shorter
0.046 Deck Clearance
1.570 Comp Ht - Egge 343 2V cast pistons
14.0cc Dish Volume - Egge 343 2V cast pistons
55.5cc Comb Cham - Stock AMC 58cc heads milled .015
0.045 thk x 4.265 dia FelPro Head Gasket


[b]Using 4cc for Egge 343 4V Pistons in an AMC 360:[/b]

Result: [b]10.34:1 Static CR [/b]
Unshroud valves in heads to increase volume and decrease the 10.34:1 CR

4.110 Bore - stock +.030
3.440 Stroke - stock nominal
9.208 Deck Ht - stock nominal
5.872 Re-Con Con Rod - 0.003 shorter
0.046 Deck Clearance
1.570 Comp Ht - Egge 343 2V cast pistons
4.0cc Dish Volume - Egge 343 4V cast pistons
55.5cc Comb Cham - Stock AMC 58cc heads milled .015
0.045 thk x 4.265 dia FelPro Head Gasket

 :-|