Posted By: B1Fish540
273 + MP Commando Alum. heads - 12/01/10 09:45 PM
Can this be done(Ryan?)? How much can a 273 block be bored and/or stroked? Thanks for replies.
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Wonder if I should just look for a 340 block and be done with it.
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Build a 360, it is 20 more cubes and you will not
have to fight with the restoration guys over 340
parts and costs.
Just my $0.02
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That does sound like fun..but..I want this to be a highway cruiser, too, so cant go crazy on cam and gearing. You've given me alot to think about, thanks again.
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That does sound like fun..but..I want this to be a highway cruiser, too, so cant go crazy on cam and gearing. You've given me alot to think about, thanks again.
If you even considered a 273 in the first place, the absolute best bang for buck is a free 318. A 360 would be your next choice, then a 340, and a 273 last. One of my cars has a warmed over 273 installed by previous owner, I am suprised how peppy it is ( same crank as a 340) around town, but if it has any mpg advantages, they are unseen because I keep my foot in it. You might want to rethink "cool".
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if i could get the 273 heads ported really well and then fit a 4." crank like Hot Rod Dave mentioned..THAT might get me to where i want to be for a good cruiser...what do ya think?
ps, custom pistons would be called for, i'm sure..
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if i could get the 273 heads ported really well and then fit a 4." crank like Hot Rod Dave mentioned..THAT might get me to where i want to be for a good cruiser...what do ya think?
ps, custom pistons would be called for, i'm sure..
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"what are the plans for the car? how much power do you want to make? what kind of mileage are you hoping for?"
since I want it for highway use, I'd like a motor that has the power down lower..so prob a stroked 318 or 360 would be best(?). I'd like milege to be reasonable, at least 15 mpg.
Thanks for the info on the magnum roller motor I hadnt considered the newer small blocks...but that makes sense.
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"what are the plans for the car? how much power do you want to make? what kind of mileage are you hoping for?"
since I want it for highway use, I'd like a motor that has the power down lower..so prob a stroked 318 or 360 would be best(?). I'd like milege to be reasonable, at least 15 mpg.
Thanks for the info on the magnum roller motor I hadnt considered the newer small blocks...but that makes sense.
again, how much power do you want to make? a well thought out, mildish, stock strole 318 should have no problem making 350-380 lb-ft, and 330-350 hp, and a similarly built 360 make 350-370hp and 400-430 lb ft....
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I did a 273 in my 67 Barracuda fastback back in 91 or 92.030 over TRW pistons with 318 High swirl heads(#516 I think and came out about 10:1) 1.88/1.60 valves,510/286 Erson solid,reused the stock adjustable rockers with new Prods,Holley single plane, 625 AVS and cheap headrs.
I reused the finned VCs with wrinkle paint and the original air cleaner that I modded and painted the motor Chrysler red.
904 trans w/stock histall and 3.91 gears
The car made really good power to 7K.I never dynoed or made a pass with it but it was a lot of fun and revved really fast.
Pistons might be hard to find now though
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I did a 273 in my 67 Barracuda fastback back in 91 or 92.030 over TRW pistons with 318 High swirl heads(#516 I think and came out about 10:1) 1.88/1.60 valves,510/286 Erson solid,reused the stock adjustable rockers with new Prods,Holley single plane, 625 AVS and cheap headrs.
I reused the finned VCs with wrinkle paint and the original air cleaner that I modded and painted the motor Chrysler red.
904 trans w/stock histall and 3.91 gears
The car made really good power to 7K.I never dynoed or made a pass with it but it was a lot of fun and revved really fast.
Pistons might be hard to find now though
273four, thanks for the reply! sounds like your 273 was pretty strong! I'm unable to drive a 4 speed(bad feet) but if I could i always thought a motor like the one you built along with a 4 gear would be great fun to drive! But since this car has a TF, I wanna make alotta TQ down low and only spin it to 6k or so. max if thats doable and still get the HP(380/400) I want.
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I did a 273 in my 67 Barracuda fastback back in 91 or 92.030 over TRW pistons with 318 High swirl heads(#516 I think and came out about 10:1) 1.88/1.60 valves,510/286 Erson solid,reused the stock adjustable rockers with new Prods,Holley single plane, 625 AVS and cheap headrs.
I reused the finned VCs with wrinkle paint and the original air cleaner that I modded and painted the motor Chrysler red.
904 trans w/stock histall and 3.91 gears
The car made really good power to 7K.I never dynoed or made a pass with it but it was a lot of fun and revved really fast.
Pistons might be hard to find now though
273four, thanks for the reply! sounds like your 273 was pretty strong! I'm unable to drive a 4 speed(bad feet) but if I could i always thought a motor like the one you built along with a 4 gear would be great fun to drive! But since this car has a TF, I wanna make alotta TQ down low and only spin it to 6k or so. max if thats doable and still get the HP(380/400) I want.
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I did a 273 in my 67 Barracuda fastback back in 91 or 92.030 over TRW pistons with 318 High swirl heads(#516 I think and came out about 10:1) 1.88/1.60 valves,510/286 Erson solid,reused the stock adjustable rockers with new Prods,Holley single plane, 625 AVS and cheap headrs.
I reused the finned VCs with wrinkle paint and the original air cleaner that I modded and painted the motor Chrysler red.
904 trans w/stock histall and 3.91 gears
The car made really good power to 7K.I never dynoed or made a pass with it but it was a lot of fun and revved really fast.
Pistons might be hard to find now though
273four, thanks for the reply! sounds like your 273 was pretty strong! I'm unable to drive a 4 speed(bad feet) but if I could i always thought a motor like the one you built along with a 4 gear would be great fun to drive! But since this car has a TF, I wanna make alotta TQ down low and only spin it to 6k or so. max if thats doable and still get the HP(380/400) I want.
here's what I'd do...get a 360 magnum shortblock. reuse the crank and rods. buy either RHS magnum (iron) or Edelbrock magnum heads. run kb107's at 0 deck and a .039" head gasket. if the roller lifters are in good shape, reuse them. for a cam, I'd probably look at having bullet grind you a cam. I'd see if they can regrind the stock cam using their HR272/340 lobe for both intake and exhaust, which will yield ~.544" lift with magnum 1.6 ratio rockers. if not, I'd have them grind on a new core, using a 112 LSA (factory magnum is 114). I'd install the cam at 106-108 ICL. rockers, the RHS's you could use stockers, the eddies take small block chev rockers. either way, I think I'd use Scorpion Performance rockers for small block chev in 1.6 ratio. intake, I'd use an RPM air gap. carb, I'd use an 800 eddie thunder series AVS.
a little cheaper, if you can find a whole magnum longblock that doesn't have cracked heads, just use OEM magnum heads, but do a little work to the heads--the valve job is undersized, have it redone, opening up the seats to 1.9 and 1.6", with a nivce 5 angle valve job and a 75-80 degree throat cut to open up the bowls, do some bowl blending, and open up the pushrod pinch.
converter, I'd use a tight ~2500-2800 RPM stall converter-- something that will flash up when you stomp on it, but not have a lot of slip at cruise. a lot of people seem to have good luck with dynamic 9.5" converters in that regard...
I'd swagger this combo should run on 89-91 octane, probably idle in gear at ~750 RPM with ~12-13" vacuum, probably make conservatively 350-360HP/410-420tq, and probably net you 17-20mpg highway with 2.94 or 3.23 gears.
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I'm being conservative in my estimation....
given the published flow data I've seen on RHS's and eddies, I'd think they'd be pretty close power wise, maybe 10hp more with the RHS's...but they'd also be 50+ lbs heavier.
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I'm being conservative in my estimation....
given the published flow data I've seen on RHS's and eddies, I'd think they'd be pretty close power wise, maybe 10hp more with the RHS's...but they'd also be 50+ lbs heavier.
So with a .557 cam do you still think I will get 17+ mpg? that'd be great! I like th idea of a tight convertor, too. I like those RHS heads but like you said..an added 50lbs...so I would want the eddies for sure. Anyhow, I will looking for the magnum motors now. Hopfully i can find one in a junk yard around here with low miles.