#13---701 Horsepower 420 Cubic Inch Small Block (15461)

5/26/2021


                                    701 Horsepower Small Block 

                                                

This is “so far” our high water mark for small blocks MOPARS. As you can see by the Dyno test results it was 701.6 HP @6800 and 585.9 TQ. @5100 RPM. The volumetric efficiency reached 111.5% @ 6700 RPM, also a high water mark for us. Most of our engines are pump gas engines in keeping with what the majority of our customers want, so these high numbers of race engine are very exciting to us. These power numbers are the results of many tests over several years. Not only that but the engine has a fairly small flat tappet cam and we didn’t get time to play with carb spacers and it was still a little lean on the final pull before we ran out of time on the Dyno. So what we are saying is that there is more HP available.
What did it take to do this?
Block: R-3 Siamese 4.080” with all of our race prepped kit block work.
Crank: Scat forged 4” stroke 340 Mains
Rods: Scat “H” beam 6.125”
Pistons: Diamond custom forged “High” compression & Diamond pins.
Rings: Custom low tension Total Seal/Diamond
Cam: Flat tappet HTL6872AS-6 Hughes, standard shelf cam
Heads: Indy 360-1 (for now!) with Hughes C.N.C.: W/1.6:1 Rockers
Intake: Indy 360-1 1X4 (for now) fully ported by Hughes Engines
Carb: AED Custom built 1000 CFM-4150 type
Headers: 1 7/8 Dyno Headers
Ignition: MSD dist. 6AL
I believe this basic combination is capable of even more power with some time to experiment with camshafts. The 360-1 Head (for now!) have a 1.9 installed height which should allow a roller cam with high .750”+ lift (for now!). This combination might even profit from a Dominator Carb and, we should look at 2” or larger headers – and this is a small block!!!
Notes: Even with these large port Indy 360-1 Heads (for now!); the torque down low @3200 RPM was very strong. You gotta love that Flat Tappet cam. If we would have had more time to play with the carb & collectors, the dip in the curves from 3500 to 4200 rpm could have been fattened up to.
This was with a standard volume oil pump (62 PSI) and the bearings looked beautiful after the testing.
Now explain to me again why you think need a roller cam and a high volume oil pump. 
            Click on chart to enlarge                                                               Click on graph to enlarge
           
 

 

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