423 SBC prediction

[prairiehotrodder]

I've talked about this motor before, its just about done and will likely be raced this weekend. What kind of power and times do you guess ?

Dart little M block. 4.165 bore, 3.875 stroke
AFR CNC 227 heads with T&D shaft 1.5 rockers
13.27 CR on av gas
AFR titan composite single plain intake with QFT 1050 carb (4150 base)
Moroso power pan (the best one with the side kickouts)
comp TK solid roller cam 12-863-9 263 / 272 .648 / .645 108 LSA installed at 106


Most of the parts were in a 383 with 11.1 CR and an 850 carb and ran 10.60's in a 78 lemans with a 5500 stall and 4.56 gears at 3100 pounds. In that combo the cam was in at 110 to give adequate PV clearance with the flat top pistons that were not right for the 60/40 heads.
Brian

The plan was originally to build a 427 (4 x 4.125) but the 423 is what showed up (long story)

[Elroy]

640-660

[amc fan]

600-625@6600

[novafornow]

agree with above. Looks to be head limited.

[CamKing]

645hp @ 6,700rpm

Put some 1.65 or 1.7 rockers on it, and you'll be close to 670hp

[paulzig]

655@6500RPM

9.8-9.9 @ 137-138mph

[Steve K]

My 427 SBC has the same cam, AFR 210's, 11:1 compression and a tunnel ram with dual carbs, 1.6 rockers and other junk that cost a lot. It did 660 hp and 600 tq on the dyno. I will say though that I didn't have the confidence in the dyno operator as it wasn't the guy I usually use but we did do the number. Engine feels like its got all of that so it might be accurate. You'd be in that range with your engine. Feel free to pm me and I can fill you in. I'm in Regina.

[Gregory]

Go to www.performancetrends.com and download their Engine Analyzer Pro (it’s free for ten days) and carefully enter
your data and you will get your answer. You’ll also be able to move things around and see how it changes the output My 408 SBC( 600-615HP) on my dyno was “very” close to the Engine Analyzer Pro prediction - good data in good data out.
I see posts all the time asking “what do you think it will make...” The down load is free - what am I missing?

[8989]

650 @ 6900. I just did my 421 with the same exact head and titanium retainers and it made
702@ 7000rpm
685@ 7500 and still made 665@8000. Those heads are pretty nice. Mine is a dry sump though

[Curtis Z]

Go to www.performancetrends.com and download their Engine Analyzer Pro (it’s free for ten days) and carefully enter
your data and you will get your answer. You’ll also be able to move things around and see how it changes the output My 408 SBC( 600-615HP) on my dyno was “very” close to the Engine Analyzer Pro prediction - good data in good data out.
I see posts all the time asking “what do you think it will make...” The down load is free - what am I missing?

Amen

[prairiehotrodder]

picked up a tenth. I'm sure there is a cork in the system that just needs to be found.

the new combo gained 2 points of CR,
40 cubic inches
200 cfm more carb

and what ? 20 hp ?

[BrazilianZ28Camaro]

picked up a tenth. I'm sure there is a cork in the system that just needs to be found.

the new combo gained 2 points of CR,
40 cubic inches
200 cfm more carb

and what ? 20 hp ?

I run a very similar engine combo besides I have a Victor ram and two 750s, MFT cam and Standard studed rockers.

My best ET is 6.32@111mph in the eigth mile wich is all we're allowed to run overhere in Brazil. Should equals to 9.8x in the quarter.

My '71 Z28 Weight 3300lbs, runs with a TH350 and 4500 stall converter. 430 gears and 29x10.5 Hoosiers.Stock suspension with caltracs.Never dynoed the motor but I'll guestimate close to 700 HP.

I'm pretty sure your missing something with the new setup.

Can you give us a complete description of your car, transmission, fuel system, exaust system,etc?

[GARY C]

I've talked about this motor before, its just about done and will likely be raced this weekend. What kind of power and times do you guess ?

Dart little M block. 4.165 bore, 3.875 stroke
AFR CNC 227 heads with T&D shaft 1.5 rockers
13.27 CR on av gas
AFR titan composite single plain intake with QFT 1050 carb (4150 base)
Moroso power pan (the best one with the side kickouts)
comp TK solid roller cam 12-863-9 263 / 272 .648 / .645 108 LSA installed at 106


Most of the parts were in a 383 with 11.1 CR and an 850 carb and ran 10.60's in a 78 lemans with a 5500 stall and 4.56 gears at 3100 pounds. In that combo the cam was in at 110 to give adequate PV clearance with the flat top pistons that were not right for the 60/40 heads.
Brian

The plan was originally to build a 427 (4 x 4.125) but the 423 is what showed up (long story)

I don't think the AFR 227 head is what is needed for that CI, the set I tested for a 421 only flowed about 309 CFM and the engine probably made 625 to 650, I would want in excess of .700 lift on the intake to try to get all i could from those heads.

[BigBro74]

I agree with Diego- something missing. If I had to choose an easy thing to try it would be to use an actual race fuel.
I have never used av gas- I know it has the octane u need, and I know it is probably easier/less expensive for you but if you are turning it pretty hard it may just work better. Could u just get something like CAM 2 up there To try? Maybe I’m out to lunch on this - if so- please disregard ...
You will find something if you work at it—
Jason

BTW- what were the mph? Same? Rpms through the same?

[GARY C]

I agree with Diego- something missing. If I had to choose an easy thing to try it would be to use an actual race fuel.
I have never used av gas- I know it has the octane u need, and I know it is probably easier/less expensive for you but if you are turning it pretty hard it may just work better. Could u just get something like CAM 2 up there To try? Maybe I’m out to lunch on this - if so- please disregard ...
You will find something if you work at it—
Jason

Not sure that 101 low lead is enough for 13.2 compression, VP110 is border line at 13.5, all the circle track guys that buy fuel from me for their 420+ inch engine either run 112 or 114.