383 Dyno Results
03-30-2003, 08:28 PM
#16
Registered User
Join Date: Oct 2000
Location: Charlotte, NC
Posts: 786
Yeah, you can make up to ~500hp with 255cfm.. if it's done right.
The problem with those intake #'s, and on the exhaust too, is that the midlift numbers were horrific. Giant exhust ports, poor shape, giant venturi's, and a near stock roof along with a near stock & f'd up short side. The stuff I had & the numbers from other people that tested their stuff pretty much saw the same from what I was told. I can't even begin to tell ya how poor the quality was. The ports weren't even consistent, hell I put the BEST one on that flowsheet. The components were cheap stock replacement stuff, the valvejob was ground in and not even close to being consistent & farther yet from being "right." Even worse, they didn't even pick parts that actually fit together on them. With zero run time they managed to just about ruin a set of $150 Ti retainers. I couldn't get the retainer out of the inner spring, and didn't realize how badly the interference was until even prying with a screwdriver I had one hell of a time getting them to seperate.
I expected bad, but I've seen DIY jobs that were more consistent. How one manages to only get that little bit of air through something, and still literally have 1/2-2/3 of the ports leaking like a sieve... I still have that one set sitting here. The guy can't sell them how they are now, and they'd take quite a bit of $ to even make them safe to run. No use making garbage into safe garbage, so the customer went back to those guys. Of course they've just ignored him & he's left with $1500+ doorstops. If anyone wants them to cut up, for the components, or to hold things down on windy day's the guy would likely part with them for next to nothing.
Like some of us said.. be very grateful you haven't hosed your shortblock & keep an eye out for white smoke & dropping coolant level. If you had decent heads you'd pick up a good bit of power across the board, and if you had great heads you'd likely be in the 430-450rwhp range.
Good luck with it
The problem with those intake #'s, and on the exhaust too, is that the midlift numbers were horrific. Giant exhust ports, poor shape, giant venturi's, and a near stock roof along with a near stock & f'd up short side. The stuff I had & the numbers from other people that tested their stuff pretty much saw the same from what I was told. I can't even begin to tell ya how poor the quality was. The ports weren't even consistent, hell I put the BEST one on that flowsheet. The components were cheap stock replacement stuff, the valvejob was ground in and not even close to being consistent & farther yet from being "right." Even worse, they didn't even pick parts that actually fit together on them. With zero run time they managed to just about ruin a set of $150 Ti retainers. I couldn't get the retainer out of the inner spring, and didn't realize how badly the interference was until even prying with a screwdriver I had one hell of a time getting them to seperate.
I expected bad, but I've seen DIY jobs that were more consistent. How one manages to only get that little bit of air through something, and still literally have 1/2-2/3 of the ports leaking like a sieve... I still have that one set sitting here. The guy can't sell them how they are now, and they'd take quite a bit of $ to even make them safe to run. No use making garbage into safe garbage, so the customer went back to those guys. Of course they've just ignored him & he's left with $1500+ doorstops. If anyone wants them to cut up, for the components, or to hold things down on windy day's the guy would likely part with them for next to nothing.
Like some of us said.. be very grateful you haven't hosed your shortblock & keep an eye out for white smoke & dropping coolant level. If you had decent heads you'd pick up a good bit of power across the board, and if you had great heads you'd likely be in the 430-450rwhp range.
Good luck with it
03-30-2003, 08:34 PM
#17
Registered User
Join Date: Aug 2002
Location: Red Oak Texas
Posts: 1,509
The 255 at .500is not bad if it is paired with better #'s below that.
The bad part is
.100-63
.200-123
.300-176
.400-223
The .200 lift # is usually 135-139 on a good head.
The .300 lift # is usually 185-190 on a good head.
The .400 lift # is usually 233-240 on a good head.
IF the # were
.100-65
.200-135
.300-187
.400-237
.450-250
.500-255
.550-258
.600-256
than 255 cfm at .600 is fine but with these low #'s 255 is not very good.
The heads that are on this 383 flowed over 275 at .600 but had low lift #'s that were comparable to the flow #'s on the 255 cfm head.
NightTrain66
The bad part is
.100-63
.200-123
.300-176
.400-223
The .200 lift # is usually 135-139 on a good head.
The .300 lift # is usually 185-190 on a good head.
The .400 lift # is usually 233-240 on a good head.
IF the # were
.100-65
.200-135
.300-187
.400-237
.450-250
.500-255
.550-258
.600-256
than 255 cfm at .600 is fine but with these low #'s 255 is not very good.
The heads that are on this 383 flowed over 275 at .600 but had low lift #'s that were comparable to the flow #'s on the 255 cfm head.
NightTrain66
03-30-2003, 08:49 PM
#18
Registered User
Join Date: Nov 1999
Location: Shreveport La.
Posts: 541
I agree with you both totally. I've brought these posts to the attention of "certain people", but they/he hold true to there stories. If this was a few months back, I'd argue the topic, but I've have flown at least 3 sets on a diffrent bench, and recieved the same results as yours. I chalk it up to, "i got lucky" and leave it at that.---Jason
03-31-2003, 10:55 AM
#20
Registered User
Join Date: Jan 2003
Posts: 5
Hey Guys, sorry I haven't responded. I was at the race all day yesterday and just got to look at the respones.
To answer some of the questions out there, yes, these are the infamous heads from Pro Perf. that Lloyd is mentioning. I thought with his touch up they would be serviceable, but maybe they were to far gone.
I believe the dyno was a dyno-jet and not a mustang, and yes we would tweak something and re-dyno Lloyd. We mainly just advanced timing. We are both kind of new with LT1 edit and didn't want to mess anything up. And Cajun we are running 1.6 rockers as well.
One thing that I have been wondering about is the Knock Retard. We didn't test it on the dyno this time, but we did get up to 9 degrees in testing on the street before. Would KR rob that much horsepower? That is the next thing we will try, but I doubt that will make up for all that lost power. We have also talked about doing something with the ignition (MSD) because the graphs got a little jittery on the top end. Does that sound like ignition?
Thanks again for all the replys.
To answer some of the questions out there, yes, these are the infamous heads from Pro Perf. that Lloyd is mentioning. I thought with his touch up they would be serviceable, but maybe they were to far gone.
I believe the dyno was a dyno-jet and not a mustang, and yes we would tweak something and re-dyno Lloyd. We mainly just advanced timing. We are both kind of new with LT1 edit and didn't want to mess anything up. And Cajun we are running 1.6 rockers as well.
One thing that I have been wondering about is the Knock Retard. We didn't test it on the dyno this time, but we did get up to 9 degrees in testing on the street before. Would KR rob that much horsepower? That is the next thing we will try, but I doubt that will make up for all that lost power. We have also talked about doing something with the ignition (MSD) because the graphs got a little jittery on the top end. Does that sound like ignition?
Thanks again for all the replys.
03-31-2003, 06:50 PM
#21
Registered User
Join Date: Nov 1999
Location: Shreveport La.
Posts: 541
Spikes on the top end can be a result of not enough fuel,or a failing ignition part. If all you did was mess with the timing, you may want to get some paramiters for the fuel curve. 9 degrees of knock will deffinatlly kill some power, but so will tuning. Sounds like a few things need to be worked out and you would be doing better. Like stated earlier, disable the knock sensor and try that.
03-31-2003, 11:33 PM
#22
Registered User
Join Date: Aug 2002
Location: Red Oak Texas
Posts: 1,509
I also remeber the chambers had about 30 cc's removed (exagerated) from them and the spark plugs would have SEVERAL spark plug threads exposed (not exagerated) and tmaybe that is causing you some "hot spots" or something.
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Maybe????
NightTrain66
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Maybe????
NightTrain66
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