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1000 for a 360 seems a bit steep, is it rebuilt?

It will be a low compression engine if its not, but still a better starting point than the 318. Youd probably be better off to spend money upping the compression than on the Magnum heads depending on how much they cost, the 360 heads flow decently. If you can get 9:1 compression, with headers, aftermarket intake and 650 carb, and a Comp XE268 350 horse would be no problem.

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1000 for a 360 seems a bit steep, is it rebuilt?

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where did that number come from??? He said $175.00 delivered where I read it.

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1000 for a 360 seems a bit steep, is it rebuilt?

It will be a low compression engine if its not, but still a better starting point than the 318. Youd probably be better off to spend money upping the compression than on the Magnum heads depending on how much they cost, the 360 heads flow decently. If you can get 9:1 compression, with headers, aftermarket intake and 650 carb, and a Comp XE268 350 horse would be no problem.

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the thing about Magnum heads is, if they're stock and don't have hardened valve seats, they're almost sure to have cracks. Small cracks aren't usually an issue mechanically, but why pay $250 for a set of heads that could have problems, when you could buy a set of RHS heads for $335.16/ea. The RHS heads have better flow, tighter numbers, dry exhaust bolt holes, and better side casting without freeze plugs.

http://www.compperformancegroupstores.co...Code=ChryMagnum

The main point is, if you have to have work done on the stock heads, OOTB RHS heads are just as cheap.

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Oh ALRIGHT, I thought he said for a grand!

250 isnt too much for the heads. If its a low mileage engine without alot of ridge though you may be better off to knock the ridge off, hone it, and buy some pistons to get the compression up nice and high. It will be in the low 8s or maybe even high 7s most likely.

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Oh ALRIGHT, I thought he said for a grand!

250 isnt too much for the heads. If its a low mileage engine without alot of ridge though you may be better off to knock the ridge off, hone it, and buy some pistons to get the compression up nice and high. It will be in the low 8s or maybe even high 7s most likely.

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wait is it even worth it then?you said before with my 318 combo i could get 9 to 1 compression?

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Oh ALRIGHT, I thought he said for a grand!

250 isnt too much for the heads. If its a low mileage engine without alot of ridge though you may be better off to knock the ridge off, hone it, and buy some pistons to get the compression up nice and high. It will be in the low 8s or maybe even high 7s most likely.

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wait is it even worth it then?you said before with my 318 combo i could get 9 to 1 compression?

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I said IF YOU could get 9:1 compression. To me the 360 is a better starting point, especially with stock heads because the 360 heads will flow better than your 318 heads (theyre basically 340 heads). If it were my engine Id open it up, if it doesnt have much ridge Id knock the ridge off, put in some KB Hyper pistons to get 9.5:1 compression, and slide in an XE268, RPM intake, 600 or 650 carb, and headers, and you will have more power than a 340 would with the same mods.

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believe me, the stock magnum seats aren't hard enough. Having seen an entire set of heads wiped, and having done more research than most on magnum combos, I know that new valve seats are necessary. If you already have the heads, great, just be forewarned.

As for compression, you can easily get 9.5:1, which is where I'm at, with new pistons, rings, and a thin head gasket. Just watch out for piston to valve clearance onceyou get close to zero deck.

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i think i can get at least 350 horse with the combo im doing

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i think i can get at least 350 horse with the combo im doing

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I don't know about that. I know of a few magnum headed 360's that dynoed 375hp but they had more compression than you and more cam. With the combo you have, if you are trying to do this to an old tired smogger engine I'm thinking more like 300-330hp tops.

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well now im getting an engine with 85,000 miles off an awesome moparts member with a 727 trans


im really excited now!i cant wait!

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nice score.

keep it simple, good cam, pistons, and factory "J" heads, you'll have more than enough power.

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Amen.
You can make good power with nothing but a cam switch and using the right valve springs for the cam. Even using stock pistons you can make that 360 really wake up. A good intake like and LD340 or Airgap and 650 or 700 Carb and it will come alive. Believe me.

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remember guys, erik is 16 and not made of money....I guess I don't see doing a piston swap without a bore job, and you're probably looking at $700+ for some KB107's, rings, getting the new pistons pressed on the rods, & bore & hone....


$175 is a very good deal if the shortblock is a good, running engine, and a fair deal if it needs to be rebuilt. I'd probably tear it down at least checking the conditions of the bearings, and maybe replacing them and the rings...

sounds like you already have the mag heads, so I'd use those. they flow a little better than stock 360 heads with smaller ports (better velocity) and smaller chambers (more compression). with the .028" thick MP or MR. gasket head gaskets and a 63ish cc mag chamber, you're looking at about 8.7-8.9:1 compression with stock 360 pistons. if you didn't have them, the stock 360 heads aren't bad, either. definitely use the GM3100 springs/retainers and the mag locks--comp doesn't have a recommendation for springs for mag heads, because they don't make any retainers for them....but the GM springs are a good generic performance spring, in the regards that they're 330-365 lb/in rate, will have 90-100lbs seat pressure at they're typical install height on a mag head (~1.6-1.62" or so), and coil bind at 1.06", so you're looking at about .480-.490 max lift, so they're very comparable to a comp 901 on an LA head.

definitely use some headers, I'd probably get the summit or flowtech ones based on price (flowtech ones are $280 ceramic coated from summit).

intake, IIRC the street dominator is a single plane, longish runners, and 318 port size. should be an OK intake, if you already have it, but a better intake for your combo would be a dual plane, I'd probably look to the stock 360 manifold (on the cheap) or an eddie performer (next cheapest, will gain you a little low end torque, but cost you a little peak HP over a stock 360 intake) or a eddie RPM/LD340/air gap (most expensive).

cam. remember, magnums use 1.6 ratio rockers, so to stay "safe" on the lift with the GM springs (without knowing the exact installed height of the springs on YOUR heads), you're looking at a cam with a lobe lift of about .303" max (ends up being .485" lift with 1.6's, or .455" lift with 1.5's.

here's the cams I'd look at:


summit k6901

cheapest, $100 for cam/lifters is 276/286 adv. dur, .441" lift with 1.5 rockers, .470 with mag rockers, 218/228 .050 dur, 114 LSA, 53 degrees overlap. with that much overlap, should give a pretty lopey idle, but the .050 duration numbers being rather tame, should give good drivability and street manners.

MP .450/.455" lift cam
268/272 adv. dur, .45/.455 lift with 1.5 rockers, .480/.485 lift with mag rockers, 228/231 .050 duration, 110 LSA 50 degrees overlap. similar idle to above cam, more .050 duration will give more peak power potential, and provide it higher in the rev range, the narrower LSA will boost some of the midrange torque loss due to the increased .050 duration. should behave very similarly to a comp XE268 in a 9:1 LA 360.

comp XE256 256/268 adv, 212/218 .050, .447/.455 lift w/1.5 rockers, .477/.485" lift with 1.6's, 42 degrees overlap. should have a near stock idle, and make very good torque. should have stronger idle-3500RPM power/torque than the above, and probably won't sacrifice much in the upper RPM regions either. for a heavy B body, and my preference for being stealthy, this is the cam I'd use, especially if you plan on keeping highway friendly (2.76-2.94) gearing.

comp 268H 268/268 adv, 218/218 .050, .454/.454" lift with 1.5's, .484/.484" lift with 1.6's, 110 LSA, 48 degrees overlap. would probably fall somewhere between the summit cam and the XE256 in idle quality and performance.


for reference, I have a stock long block 360, some home bowl ported 360 heads, headers, eddie air gap, 600 eddie carb, and a comp XE262 in my 3900lb 5th ave. I used the head gaskets out of the standard felpro gasket kit (.054" compressed), my calculated compression based on my pistons depth-in-hole is about 7.8:1. my car idles with about 13" vaccuum in gear at 750 RPM (17" in park at about 900 RPM) so it has a very slight lope. my 3900 lb 5th ave, with an A500 tranny, 3.55's and 27" tires moves very good, and can keep up with a LX 300C hemi from a roll, so I'm guessing it's a low 14 second car, maybe nipping high 13's. the XE262 has too much lift on the exhaust lobe for your springs, but the 268H should perform nearly identical (if not better) with the mag 1.6 rockers as an XE262 with the LA 1.5's

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patrick is very good for info.

you dont even understand how much this helps me out.id be lost if i didnt have moparts!

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remember guys, erik is 16 and not made of money....I guess I don't see doing a piston swap without a bore job, and you're probably looking at $700+ for some KB107's, rings, getting the new pistons pressed on the rods, & bore & hone....


$175 is a very good deal if the shortblock is a good, running engine, and a fair deal if it needs to be rebuilt. I'd probably tear it down at least checking the conditions of the bearings, and maybe replacing them and the rings...

sounds like you already have the mag heads, so I'd use those. they flow a little better than stock 360 heads with smaller ports (better velocity) and smaller chambers (more compression). with the .028" thick MP or MR. gasket head gaskets and a 63ish cc mag chamber, you're looking at about 8.7-8.9:1 compression with stock 360 pistons. if you didn't have them, the stock 360 heads aren't bad, either. definitely use the GM3100 springs/retainers and the mag locks--comp doesn't have a recommendation for springs for mag heads, because they don't make any retainers for them....but the GM springs are a good generic performance spring, in the regards that they're 330-365 lb/in rate, will have 90-100lbs seat pressure at they're typical install height on a mag head (~1.6-1.62" or so), and coil bind at 1.06", so you're looking at about .480-.490 max lift, so they're very comparable to a comp 901 on an LA head.

definitely use some headers, I'd probably get the summit or flowtech ones based on price (flowtech ones are $280 ceramic coated from summit).

intake, IIRC the street dominator is a single plane, longish runners, and 318 port size. should be an OK intake, if you already have it, but a better intake for your combo would be a dual plane, I'd probably look to the stock 360 manifold (on the cheap) or an eddie performer (next cheapest, will gain you a little low end torque, but cost you a little peak HP over a stock 360 intake) or a eddie RPM/LD340/air gap (most expensive).

cam. remember, magnums use 1.6 ratio rockers, so to stay "safe" on the lift with the GM springs (without knowing the exact installed height of the springs on YOUR heads), you're looking at a cam with a lobe lift of about .303" max (ends up being .485" lift with 1.6's, or .455" lift with 1.5's.

here's the cams I'd look at:


summit k6901

cheapest, $100 for cam/lifters is 276/286 adv. dur, .441" lift with 1.5 rockers, .470 with mag rockers, 218/228 .050 dur, 114 LSA, 53 degrees overlap. with that much overlap, should give a pretty lopey idle, but the .050 duration numbers being rather tame, should give good drivability and street manners.

MP .450/.455" lift cam
268/272 adv. dur, .45/.455 lift with 1.5 rockers, .480/.485 lift with mag rockers, 228/231 .050 duration, 110 LSA 50 degrees overlap. similar idle to above cam, more .050 duration will give more peak power potential, and provide it higher in the rev range, the narrower LSA will boost some of the midrange torque loss due to the increased .050 duration. should behave very similarly to a comp XE268 in a 9:1 LA 360.

comp XE256 256/268 adv, 212/218 .050, .447/.455 lift w/1.5 rockers, .477/.485" lift with 1.6's, 42 degrees overlap. should have a near stock idle, and make very good torque. should have stronger idle-3500RPM power/torque than the above, and probably won't sacrifice much in the upper RPM regions either. for a heavy B body, and my preference for being stealthy, this is the cam I'd use, especially if you plan on keeping highway friendly (2.76-2.94) gearing.

comp 268H 268/268 adv, 218/218 .050, .454/.454" lift with 1.5's, .484/.484" lift with 1.6's, 110 LSA, 48 degrees overlap. would probably fall somewhere between the summit cam and the XE256 in idle quality and performance.


for reference, I have a stock long block 360, some home bowl ported 360 heads, headers, eddie air gap, 600 eddie carb, and a comp XE262 in my 3900lb 5th ave. I used the head gaskets out of the standard felpro gasket kit (.054" compressed), my calculated compression based on my pistons depth-in-hole is about 7.8:1. my car idles with about 13" vaccuum in gear at 750 RPM (17" in park at about 900 RPM) so it has a very slight lope. my 3900 lb 5th ave, with an A500 tranny, 3.55's and 27" tires moves very good, and can keep up with a LX 300C hemi from a roll, so I'm guessing it's a low 14 second car, maybe nipping high 13's. the XE262 has too much lift on the exhaust lobe for your springs, but the 268H should perform nearly identical (if not better) with the mag 1.6 rockers as an XE262 with the LA 1.5's

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patrick is very good for info.

you dont even understand how much this helps me out.id be lost if i didnt have moparts!


oh yeah.

im getting this 360 that runs but its a truck engine and trans.

besides the oil pan and oil pump what else do i have to change.

someone told me the trans is too short?

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its a two wheel drive truck so the trans is the same as the car one.

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oh yeah.

would zero decking it or taking a bit off the block help at all?

maybe thats a better alternative than new pistons.

and prob cheaper

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oh yeah.

would zero decking it or taking a bit off the block help at all?

maybe thats a better alternative than new pistons.

and prob cheaper

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what do you think i would be at compression wise?

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any aftermarket cam will have the pushrod oiling lifters except maybe mopar performance ones. everyone else (comp, crane, summit, lunati) lists the same lifters for AMC and chrysler.

w/o decking or new pistons, with the mag heads and stock LA shortblock, if you use the think Mr. gasket/MP head gaskets (.028" thick) and your mag heads are stock 63ccish chambers, you'll be at about 8.6-8.7:1 compression.

decking will most likely be more expensive than the cost of the pistons, but then, you probably would want to actually get the block bored if you're buying new slugs.

I'd be leery of even that much lift on stock mag valve springs. remember, on the magnum engine that will be .470/.470 lift. I'd use the GM 3100 springs/retainers with that cam.

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that cam w/1.6 rockers will end up having specs in .050 duration and lift similar to a comp XE262.

dulcich made 335hp/400tq with a stock long block 360 from the early 80's, hooker headers, and a comp XE262.

see article:
http://compcams.com/Community/Articles/Details.asp?ID=-409383413

with the mag heads giving slightly better flow, more velocity, and 3/4 of a point higher compression, I'd probably put the motor in the 350-355HP/410-420tq range as long as the bottom end is in good shape with good ring seal.

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comp XE262 is 262/270 adv, 218/224 .050, .462/.470 lift, 110 LSA, 46 degrees overlap.

the summit K6901 (with magnum 1.6 ratio rockers) is 276/286 adv, 218/228 .050 duration, .470/.470 lift, 114 LSA, 53 degrees overlap

since .050 duration is near identical, these cams should have similar RPM ranges. the 114 LSA of the summit cam might sacrafice a little low end/midrange torque and carry the powerband slightly higher. the additional 7 degrees of overlap should make the idle lumpier. similar .050 duration and lift numbers mean they should make similar power, if head flow is similar.

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so in ther words the cam is fine then?

thanks patrick in advance for your help.

and you too hotroddave!

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that cam w/1.6 rockers will end up having specs in .050 duration and lift similar to a comp XE262.

dulcich made 335hp/400tq with a stock long block 360 from the early 80's, hooker headers, and a comp XE262.

see article:
http://compcams.com/Community/Articles/Details.asp?ID=-409383413

with the mag heads giving slightly better flow, more velocity, and 3/4 of a point higher compression, I'd probably put the motor in the 350-355HP/410-420tq range as long as the bottom end is in good shape with good ring seal.

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oh yeah idk if you noticed but you know they made 335 horse with a block bored 40 over.

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the overbore will add 7 cubic inches. it won't really affect power at all, maybe 1-2% at most over a similarly built standard bore engine

condition of the bores (are they round? tapered?), and ring seal quality will have a larger effect on power than .040" more bore will

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