If you were building a engine for .........
#2879667
01/24/21 10:46 PM
01/24/21 10:46 PM
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Joined: Oct 2003
Posts: 11,686 W. Kentucky
justinp61
OP
I Live Here
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OP
I Live Here
Joined: Oct 2003
Posts: 11,686
W. Kentucky
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A mid-late 80's pick up cruiser. I have enough stuff to build a 340 or a 408. The truck would have air and be used for (some) daily driving, cruising and occasionally towing my 18' aluminum boat. Most likely I'll run a hydraulic flat tappet but may consider a hydraulic roller, nothing wild, just something that will make good power and not need a very loose converter. The truck would start with either a 904 or 727 and later maybe a 93 or so overdrive transmission. Gears would be either 3.21 or 3.55's. Initally I'll run a carb but would like to try fuel injection after everything is sorted out. Either engine will need new pistons as my Edelbrocks have been milled to 55cc. The 340 was 11.4-1 and the 408 was 10.8-1 with these heads and a Fel-Pro 1008. The heads flow in the mid 290's.
So, what would you guys build?
Last edited by justinp61; 01/24/21 10:48 PM.
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Re: If you were building a engine for .........
[Re: calrobb2000]
#2880089
01/25/21 07:09 PM
01/25/21 07:09 PM
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Joined: Jan 2003
Posts: 20,894 A collage of whims
topside
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 20,894
A collage of whims
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Cruise & tow RPM will help with cam selection, but a stroked 360 sounds best for that. Did a 406" 360 for my 74 Duster. Cast crank & pistons, 340 rods, 9.5:1 CR, Thermoquad on Eddy Performer, iron 360 heads, pre-existing cheap headers, 8-qt pan & tray. AT, AC car with 3.21s, 275/60R15s (28" tall), street car for city & highway. Engle hyd FT with 214/224 @ .050 and .470/.504 lift, on 110 IIRC. Great street manners, plenty of torque, ran strong & pulled 17 MPG @ 70-75. That CR was pushing it with iron heads, aluminum would have been better. Avoid the MP "stroker 360" pistons, they're actually for SBC rods.
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Re: If you were building a engine for .........
[Re: topside]
#2880332
01/26/21 10:38 AM
01/26/21 10:38 AM
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Joined: Jan 2003
Posts: 10,016 Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,016
Frostbitefalls MN (Rocky&Bullw...
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If you are serious about overdrive and 3.21 to 3.55 rear gear, the cam choice better be real short duration. I would opt for a 3.91 rear gear , 408 cubes and O.D. that will allow a bit more cam as your cruise rpm in OD will rise to somewhere around 2000 or a bit more. A custom lockup converter will almost be a must.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: If you were building a engine for .........
[Re: DaveRS23]
#2880509
01/26/21 04:50 PM
01/26/21 04:50 PM
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Joined: Aug 2003
Posts: 43,292 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,292
Bend,OR USA
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I have 3.91s behind my 518. That is a very good combination. 3.55s or especially 3.23s would seem too steep to me. I tried 3:73, 3:91, 4:10 and 4:30 in my old pump gas Duster with the 518 C.I. low deck 400 stroker motor. That car ran the same ET and MPH, within .10 ET and .3 MPH, in both the 1/8 mile and 1/4 mile The car did spend less time in high gear with the lower 4:30 ratio in it than it did with the 3:73 and 3:91 in both the 1/8 mile and 1/4 mile The higher ratio(4:10 and 4:30) would give it more starting line ratio than the other lower (3:73, 3:91) rear ratio would which in turn affected the stall speed in the converter, especially in low gear Dave when you say 518 are you talking about the C.I. or trans type?
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: If you were building a engine for .........
[Re: Cab_Burge]
#2880793
01/27/21 09:42 AM
01/27/21 09:42 AM
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Joined: Jan 2003
Posts: 12,256 Benton, IL.
DaveRS23
Special needs idiot
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Special needs idiot
Joined: Jan 2003
Posts: 12,256
Benton, IL.
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540 Hemi, 518OD, 3.91s in 8 3/4.
Unlike the new engines, our old engines especially with some cam, need more RPM to be comfortable cruising. My '18 Hemi Ram will lope along on the hiway at 1,600RPM. But my 2nd gen Hemi really wants over 2,200RPM to cruise comfortably. So, I think it is very possible to get too low of a cruising RPM with our engines. Wedges might need a few less RPM and EFI could help. But there might be some trial and error to find out how low an RPM the combo would be comfortable cruising with.
You've got the heads, so my combo would be: 408, 518OD, 3.91s. The cam profile will be the big determinate on how the thing cruises.
Would you be able to run 87 with 10.8 comp ratio especially when in OD or when towing?
Master, again and still
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