Afr heads and new tune on my 383
06-07-2013, 02:20 PM
#22
Its fun to drive for sure... i just hope i didnt hurt my newly rebuilt trans too bad last night... I lost 4 gear for a bit when screwing around LOL
This morning it shifteed fine, got home and it was low on fluid. Must have been lopw when I lost 4th... and possibly on the dyno yesterday.
This morning it shifteed fine, got home and it was low on fluid. Must have been lopw when I lost 4th... and possibly on the dyno yesterday.
06-07-2013, 02:51 PM
#23
His reasoning for the dished pistons was "yeah, you could bump your compression up by two points likely. Your tune would have to be very spot on to run the crap gas we have around here, and 10.5:1 gives you the option of running a bit of boost in the future, or just sprayng it."
06-07-2013, 07:30 PM
#26
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Lol couldnt agree with you more.
Stock compression is way too low for an AFR 383. I would bump it up to at least 11:1 if you want to be satisfied. But Quazz I have a question for you. How well did you plan this build? The numbers seem sort of low. I would get thinner head gaskets or get the heads milled. If tuned correctly I would also consider dome pistons since its an NA build. Then spray it a little
Take it to the track and see what it'll do.
Stock compression is way too low for an AFR 383. I would bump it up to at least 11:1 if you want to be satisfied. But Quazz I have a question for you. How well did you plan this build? The numbers seem sort of low. I would get thinner head gaskets or get the heads milled. If tuned correctly I would also consider dome pistons since its an NA build. Then spray it a little
Take it to the track and see what it'll do. 
06-07-2013, 09:47 PM
#28
What RPM are you spinning to? 847 on AFRs will want some RPM, even on a 383.
Unlocked stall will kill power a lot. Still can be a mid 11 second car, then who'd be laughing? I ran 11.7s with just about the same dyno numbers FWIW.
Unlocked stall will kill power a lot. Still can be a mid 11 second car, then who'd be laughing? I ran 11.7s with just about the same dyno numbers FWIW.
06-08-2013, 09:18 AM
#29
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and at the end of the day. that's what matters.
just remember people always talk **** about making changes to other peoples cars. and i would bet money none are willing to put their money were there mouth is and buy you the parts to do it their way.
06-08-2013, 01:04 PM
#30
The compression is a bit low for my taste and imho you would have probably been just as happy with a set of nicely ported stock heads with bigger valves...I ran ported stockers with 2.00/1.56 valves in my 383 (ported by Lingenfelter and later freshened by Eric Bradby) and loved the results...The new owner is still flogging the crap out of the car at the track..but don't get too bogged down with dyno numbers...mine only made 375 rwhp on a Mustang dyno but ran the numbers in my sig at the track at over 3600lb raceweight.
--Alan
--Alan
06-08-2013, 05:46 PM
#31
Bottom line.....you static compression ratio is too low for that cam. You made the classic mistake of going with a big-assed cam simply because you have a stroker motor. Cam spec'ing should NOT be performed on the basis of available cubic inches.....no matter what anyone tells you.
For that 10.5:1 compression ratio, your optimal cam would have an intake duration in the 220 to 224 degree range.
Going with an oversized cam with low compression prevents the cam from making the power that it could make.....especially torque and especially at lower RPMs.
http://www.kb-silvolite.com/calc.php?action=comp to calculate your Dynamic Compression.
KW
06-08-2013, 09:35 PM
#32
Thank you!! Great info! And the cam was in the car with the motor, I just made the mistake of not swapping it during the rebuild.
It looks as if the single best (cost effective) thing I can do at this point is a cam swap. Would I make better power with a custom grind at this point? I do have some cam surge present at low rpms, and better street manners would be nice. I know im going to have to have the converter tightened a bit too. Any suggestions on what direction to go?
It looks as if the single best (cost effective) thing I can do at this point is a cam swap. Would I make better power with a custom grind at this point? I do have some cam surge present at low rpms, and better street manners would be nice. I know im going to have to have the converter tightened a bit too. Any suggestions on what direction to go?
06-09-2013, 01:11 AM
#35
Additionally.....you'll have better gas mileage and better street manner (drivability) with a smaller, custom grind.
Yeah.....there'd be a lot of upside to going with a different cam......and you could probably (most likely) keep your current TC.
KW
06-09-2013, 02:21 AM
#36
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IMO i would run the car as is,since you said you're happy with its performance! I haven't seen a combo yet that couldn't be improved upon in someway.Like already said dont get hung up on dyno numbers and run it at the track.I don't feel a cam swap at this point taking cr in consideration will be worth while.
06-11-2013, 04:21 PM
#37
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My first 383 LT1 was built with a used eagle kit with the same -16 CC pistons youre talking about, I had the smaller AFR heads and the 847 cam as well.
Before the crank ate the thrust bearing the car would run mid 11s in the Oklahoma July heat.
My latest motor has more compression and a custom cam with the same heads, Day and night difference in power curve.
The first motor would "build" power with RPM and would move good (had to rev the pee out of it to trap close to 120). This new motor has power off idle and gets scary as the RPM increases...lol
It may sound funny but if you get the itch the person that said change the pistons probably has the best advise to make the number on the Dyno.
Before the crank ate the thrust bearing the car would run mid 11s in the Oklahoma July heat.
My latest motor has more compression and a custom cam with the same heads, Day and night difference in power curve.
The first motor would "build" power with RPM and would move good (had to rev the pee out of it to trap close to 120). This new motor has power off idle and gets scary as the RPM increases...lol
It may sound funny but if you get the itch the person that said change the pistons probably has the best advise to make the number on the Dyno.
06-11-2013, 04:27 PM
#38
I'm just saying do it once and be done, those heads with the 847 and 12.5:1 would be a sweet package...you could probably sell your current pistons for close to what flat tops would cost you, so little $$ out of pocket except new $40 victor head gaskets and $200 to rebalance the rotating assembly. $240 < $450 custom AI cam.
06-12-2013, 10:27 AM
#39
If what he's concerned about at this point is making peak power on the dyno, then changing pistons.....or milling the heads.....or both.....to get to about 12:1 static CR would be the way to go.
But.....if he wants to improve his engine efficiency easily and economically, then getting a cam custom spec'ed would be the way to go.
It's all about choices.....and what he wants out of his car.
KW
