Don Terrill’s Speed-Talk

Orr89rocz wrote:

That'll make about 500hp, and start falling off after 6,300rpm.

I know you are the cam guru Mike but i am surprised to see this post. Curious as to your reasoning. I highly doubt that combo would be even peaked yet by 6300 let alone falling off. I ran a 230 deg at .050 hyd roller with .603 valve lift on a 383 with afr 195 heads and it peaked at 6250 and didnt fall off til 6600 but it had lots of exhaust duration so i guess thats why it held on.

210 heads and a 247 lobe?? I would expect that to hold beyond 6500 easily with a single plane.

You're right. I made a mistake. I calculated for a 247/255 Solid Roller, not a hydraulic roller. A 247/255 Hydraulic roller would have about 8 more degrees of seat duration.

I stand corrected.
I calculate it'll make 517hp @ 6,500rpm.

ap72 wrote:I'd lower your aim to 500 and be happy for anything over that. 550 isn't an easy feat especially when you compromise on every part due to budget.

500 is still a lot on the street.

Yeah that is true 500hp is great on the street, But if I get in the 550 rang that would be even better , I seen engine builds with smaller cams and smaller cylinder heads and lower compression then what I have make more than 500hp, thats why I believe I can aim for around 550hp or may be a little higher...

Orr89rocz wrote:

That'll make about 500hp, and start falling off after 6,300rpm.

I know you are the cam guru Mike but i am surprised to see this post. Curious as to your reasoning. I highly doubt that combo would be even peaked yet by 6300 let alone falling off. I ran a 230 deg at .050 hyd roller with .603 valve lift on a 383 with afr 195 heads and it peaked at 6250 and didnt fall off til 6600 but it had lots of exhaust duration so i guess thats why it held on.

210 heads and a 247 lobe?? I would expect that to hold beyond 6500 easily with a single plane.

Thanks for the feed back... That's what Howards cam told me that this cam will hold pass 6500 rpm if I take pass it with know problems

I know you're ambitious and anxious but I'd put a whole lot of consideration into what BigJoe and CamKing have said to expect.

swatson454 wrote:I know you're ambitious and anxious but I'd put a whole lot of consideration into what BigJoe and CamKing have said to expect.

Yeah that's true... This is what BigJoe told me>>>>>> I have built 50 or 60 383 engines very similar to your parts list. I see 540 to 550 regularly, once in a while 570 Hp with some little added mods. I have never used the cam you have selected though. It might be harder than you think to reach your gold. You should be sure to run the engine on an engine dyno to get all the horsepower you are looking for.


JOE SHERMAN RACING ENGINES

IMHO you're good to go
camking did not weigh in on the rocker ratios
IMHO you could use some more lift on the Intake but we do not know what your heads flow so can't really tell and
you are concerned about your springs-- rev kit is a plus
keeping the revs down the crank should live if there is no detonation
did you say what your quench is?
do not play with carb spacers etc--- yet- dyno first
you might want a four hole on the street with your converter and gears if you had a split manifold but...
see how the manifold you have works off idle

I would leave the 1.5 rocker for now and focus more on valve control with the springs. You should have the 8019 upgrade spring which installed at advertised height is 150 lbs seat pressure. I would feel abit more confident revving over 6500 with the springs shimmed alittle to 165-170 lbs. i did this in my afr 195 head 383 with 230 deg .603" lift cam. Afr valves are light tho so maybe 150 will get it done but my cam guy felt i needed 165 lbs and i never floated a valve to 7000 rpm where limiter was set.

Thats probably .015" shims which will bring max lift safely to .635" which your cam would exceed with 1.6's. ( i cant remember what i used but the install heights were 1.775 i believe) However thats borderline because i noticed these springs do have a tighter coil bind height than advertised so could likely get away with mild shim and 1.6 rockers. The spring specs should include .050" coil bind clearance in that .650" rating so thats more like .700" til bind. If you ran say .030-.040 to coil bind, just may clear 1.6's and still beable to shim for pressure.

wyrmrider wrote:IMHO you're good to go
camking did not weigh in on the rocker ratios
IMHO you could use some more lift on the Intake but we do not know what your heads flow so can't really tell and
you are concerned about your springs-- rev kit is a plus
keeping the revs down the crank should live if there is no detonation
did you say what your quench is?
do not play with carb spacers etc--- yet- dyno first
you might want a four hole on the street with your converter and gears if you had a split manifold but...
see how the manifold you have works off idle

On my Afr 210c competition cylinder heads they flow at 318 intake and 235 exhaust at a 600 lift very good flowing heads. But the reason I said I was worried about my spring because I swapped the solid roller springs that cam with the heads and told AirflowReseach to put hyd roller springs on my cylinder heads cause of my hyd roller cam. They max lift on the hyd roller springs are 650 lift, If i was to put 1.6 ratio rocker arms on the intake and use 1.5 ratio rockers on the Exhaust that would make lift on the cam 636/600. Do you think that 636 lift on the intake is to much for the 650 lift springs on my heads?????? Also the rev kit is for extra support to handle anything over 6500rpm was it worth buying the rev kit? I was thinking about using a 1in or2in a 4 hole HVH Super Sucker spacer whats your advice on using the carb spacer 1 or 2 inch???" What do u mean by what my quench??? Also the intake i'm using is a MOTOWN single plane rpm range on the intake is 2500-7000

Orr89rocz wrote:I would leave the 1.5 rocker for now and focus more on valve control with the springs. You should have the 8019 upgrade spring which installed at advertised height is 150 lbs seat pressure. I would feel abit more confident revving over 6500 with the springs shimmed alittle to 165-170 lbs. i did this in my afr 195 head 383 with 230 deg .603" lift cam. Afr valves are light tho so maybe 150 will get it done but my cam guy felt i needed 165 lbs and i never floated a valve to 7000 rpm where limiter was set.

Thats probably .015" shims which will bring max lift safely to .635" which your cam would exceed with 1.6's. ( i cant remember what i used but the install heights were 1.775 i believe) However thats borderline because i noticed these springs do have a tighter coil bind height than advertised so could likely get away with mild shim and 1.6 rockers. The spring specs should include .050" coil bind clearance in that .650" rating so thats more like .700" til bind. If you ran say .030-.040 to coil bind, just may clear 1.6's and still beable to shim for pressure.

Thanks for the feed back... An yes I do have the 8019 upgrade spring on my AFR 210cc heads and the springs are 650 lift, i'm not really sure about the coil bind clearance @.050, but u say it should be max at 700 right if it say 650lift for the springs???
I'm just a college kid leaning more about performance engines and getting good Tips advice &opinions for my first engine build, from guys like U . But what do u mean by the shims? I don't really understand that part, and would the shims make the springs a 165-170 lbs seat pressure instead of 150 lb seat pressure???

Hey
none of this "I'm just a college kid (or secretary) stuff
why would you think .650 springs would not work at .635?
your cam grinder should know what spring pressure you need closed and open and rate
you have the rev kit- good move IMHO which helps on the spring requiements
on the rockers choices
run what you have
change to 1.6 on the intakes
your camgrinder or cam king or big joe could advise you
do your heads flow more at .650 in the intakes?
you already have the longer exhaust
do not over think
Big joe said you are close and I agree
If you are putting together yourself do a test assembly first
check your deck height at all four corners, cam fit etc etc
without the rings the motor should turn over easily with no glitches
then clean it again , bolt holes, oil holes, everything

Afr 8019 springs

155# at 1.81" install height. At 1.21" open which is .600", theres 412# pressure

Coil bind advertised at 1.080" but i measured mine to be alittle less than that so there is a bit more room for lift than they say

1.81 - .650" is 1.16". Subtract coil bind out that leaves .080" to coil bind which is alot of clearance. Some guys here will say .040-.050" is more common. So theoretically those springs should be more capable of .680-.690" lift....

So you can run 1.6 rockers and likely could shim install height closer to 1.790" to give you closer to 165lbs seat pressure, but the rev kit should help some so it may not be necessary

wyrmrider wrote:Hey
none of this "I'm just a college kid (or secretary) stuff
why would you think .650 springs would not work at .635?
your cam grinder should know what spring pressure you need closed and open and rate
you have the rev kit- good move IMHO which helps on the spring requiements
on the rockers choices
run what you have
change to 1.6 on the intakes
your camgrinder or cam king or big joe could advise you
do your heads flow more at .650 in the intakes?
you already have the longer exhaust
do not over think
Big joe said you are close and I agree
If you are putting together yourself do a test assembly first
check your deck height at all four corners, cam fit etc etc
without the rings the motor should turn over easily with no glitches
then clean it again , bolt holes, oil holes, everything

Yes they flow more at a 650 lift my heads flow 322 on the intake and 237 on exhaust on a 650lift...

Orr89rocz wrote:Afr 8019 springs

155# at 1.81" install height. At 1.21" open which is .600", theres 412# pressure

Coil bind advertised at 1.080" but i measured mine to be alittle less than that so there is a bit more room for lift than they say

1.81 - .650" is 1.16". Subtract coil bind out that leaves .080" to coil bind which is alot of clearance. Some guys here will say .040-.050" is more common. So theoretically those springs should be more capable of .680-.690" lift....

So you can run 1.6 rockers and likely could shim install height closer to 1.790" to give you closer to 165lbs seat pressure, but the rev kit should help some so it may not be necessary

I understand a little bit thank you, and yeah I just called AFR they told me the 8019 springs don't coil bind until like 700 to 720 lift so that's pretty good.....

Desmosis:

Your parts are a little mismatched for your 550HP goal. As you are aware, horsepower is just torque times RPM divided by 5252. 550HP in a 383 CI, will happen above 6500 RPM. To do this, you can't be losing anything to the valvetrain. I would recommend a solid roller to meet your HP goals. You have good heads, you will need the single plane you have, and the crank is marginal to survive 7000 RPM which is nominally where you would like to shift.

There are many dyno curves availabe for 383's, it is a motor that has been done a lot of times. Look at those graphs for engines that are making between 550 HP and 600 HP and at what RPM they made power.

Lsx motors turn 7000 rpm all day long with hyd rollers and make big power. They have 8mm valves just like AFR's new eliminators so the valvetrain is pretty light. Should not need a solid roller to make power. I would think the 210's and 6500 rpm is all that is needed, certainly hyd roller capable. Big joe's examples are right there