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HP increase recommendation wanted

PostPosted: Fri Dec 16, 2016 10:20 am
by curtis reed
I've been reluctant to post this anywhere because most of the time these topics devolve into arguing, but I think this might be a safer place than DRR or the bullet. I am trying to figure out where best to spend my time and money to pick up some hp. What I would like to do is be able to run high 5.60s to low 5.70s all the time. Right now it runs mid 5.90s in the heat, to 5.80s when it's cooler. Best times of 1.246, 5.860 115.26, 9.399 137.05. Her is my combination.

27 roadster @2050lbs at the line. 383 SBC on alcohol. 11.6-1, single 775 carb, untouched Track-1 heads, untouched Victor jr intake, .383/.393 lobe 248/255 @ .050 106 lsa. 1.65 intake, 1.55 exhaust Yella-Terra shaft rockers. 1.76 glide, 4.88, 14-32. This is a 5.7 rod engine 3.75 stroke 4.030 running 34° timing. It hasn't shown much sensitivity to timing changes on the slip. I have never had it dynoed.

Mostly 1/8 mile leaving off the footbrake at 2000-2200 rpm, through the lights at 6600 on my data recorder. I have run this same combination for quite a few years to get the consistency worked out and it has been very good to me. The cam is really easy on valvetrain. Like most I don't have a large budget to just make wholesale changes. I'm wondering where my money might best be spent to reach my goals. Would just a cam change get me there? Just upping the compression? Is the carb holding me back or the intake and heads? What might be suggestions? Thanks for any input, let me know if I left something out.

Curtis

Re: HP increase recommendation wanted

PostPosted: Fri Dec 16, 2016 9:24 pm
by xe5800
I would up the comp more to get the use of the alky.
Pull heads machine to get comp up, a couple of gaskets and away you go.
Thats a cheap upgrade that unshould see a gain from as to how much depends on the condition of the rest of the gear.
Unless your budget is more and you could dive in further

Re: HP increase recommendation wanted

PostPosted: Sun Dec 18, 2016 7:03 pm
by curtis reed
That I could do myself. Just don't know if it will get me where I want to be. Thanks for the thoughts.

Re: HP increase recommendation wanted

PostPosted: Sun Dec 18, 2016 11:02 pm
by ou812
curtis reed wrote:I've been reluctant to post this anywhere because most of the time these topics devolve into arguing, but I think this might be a safer place than DRR or the bullet. I am trying to figure out where best to spend my time and money to pick up some hp. What I would like to do is be able to run high 5.60s to low 5.70s all the time. Right now it runs mid 5.90s in the heat, to 5.80s when it's cooler. Best times of 1.246, 5.860 115.26, 9.399 137.05. Her is my combination.

27 roadster @2050lbs at the line. 383 SBC on alcohol. 11.6-1, single 775 carb, untouched Track-1 heads, untouched Victor jr intake, .383/.393 lobe 248/255 @ .050 106 lsa. 1.65 intake, 1.55 exhaust Yella-Terra shaft rockers. 1.76 glide, 4.88, 14-32. This is a 5.7 rod engine 3.75 stroke 4.030 running 34° timing. It hasn't shown much sensitivity to timing changes on the slip. I have never had it dynoed.

Mostly 1/8 mile leaving off the footbrake at 2000-2200 rpm, through the lights at 6600 on my data recorder. I have run this same combination for quite a few years to get the consistency worked out and it has been very good to me. The cam is really easy on valvetrain. Like most I don't have a large budget to just make wholesale changes. I'm wondering where my money might best be spent to reach my goals. Would just a cam change get me there? Just upping the compression? Is the carb holding me back or the intake and heads? What might be suggestions? Thanks for any input, let me know if I left something out.

Curtis


Cam, heads, intake, and carb are really holding it back...good combo of parts for the rpm though.
Things I would do that are easy:
mill heads for true 12:1
MS 109 fuel and 950cfm carb from QF or Holley
Cam it like: 264-270@.050 and around .650 lift net
Port the heads and intake, or change the intake to a Holley or SV
I believe if you do all this you'll achieve your goal.
Brian

Re: HP increase recommendation wanted

PostPosted: Mon Dec 19, 2016 7:30 am
by curtis reed
ou812 wrote:
Cam, heads, intake, and carb are really holding it back...good combo of parts for the rpm though.
Things I would do that are easy:
mill heads for true 12:1
MS 109 fuel and 950cfm carb from QF or Holley
Cam it like: 264-270@.050 and around .650 lift net
Port the heads and intake, or change the intake to a Holley or SV
I believe if you do all this you'll achieve your goal.
Brian


Thanks. I've worked hard to maximize this combination. I won't be able to do it all at once. The heads I can cut myself, but which one item would you change first? I do have to say, I won't move away from alcohol though.

Re: HP increase recommendation wanted

PostPosted: Tue Dec 20, 2016 9:24 am
by Chad Speier
I'd want more compression.

Re: HP increase recommendation wanted

PostPosted: Tue Dec 20, 2016 9:50 am
by curtis reed
Chad Speier wrote:I'd want more compression.


Chad, I hoped you would chime in. Do you think the heads and / or intake are holding it back any at this rpm?

Curtis

Yes, I personally think a manifold might surprise you. Holley 300-25 OOB..

Re: HP increase recommendation wanted

PostPosted: Tue Dec 20, 2016 12:34 pm
by ou812
Compression will be hard to get without changing pistons or milling the heads super hard...I guess you could angle mill them and get around 13:1...and since the heads are off you might as well port them...This is what I would do first IMO.
Brian

Re: HP increase recommendation wanted

PostPosted: Sat Dec 24, 2016 10:42 am
by racear2865
Per all the comments above
up the compression. You can angle mill the head but might change the flow characteristics. Ask Chad
do sum work on the heads---chad again
Look at work on intake
carb is slightly small on Meth
I personally dont like the Vic Jr per above 300-25 with sum work--again see Chad

Damn wait a minute, just see Chad
reed

Re: HP increase recommendation wanted

PostPosted: Mon Jan 09, 2017 12:44 pm
by curtis reed
Well I got the 300-25 and was surprised at the size difference from it to the Jr. I had on the engine. Ports actually match up to my heads very well for an OOTB manifold. Had to machine, drill and tap for water lines to the back and my lean out valve, but other than that it's ready to bolt on. Thanks for the suggestion.

Curtis

Re: HP increase recommendation wanted

PostPosted: Thu Mar 30, 2017 9:30 am
by curtis reed
So the only changes I ended up making, ( because of money deficiency ), was adding the intake and changing the base plate assembly on the carb. The old one was getting stiff and worn out. I do believe I picked up hp when you see in the graph below that the flash stall is higher at the hit and it is reaching the shift point sooner. The o2 is much leaner now so I have some testing to do to see if I really did pick up. Not apples to apples because the air was just a little better on this years run. Motor sounds different also. The run names are the date followed by the time trial number.

Image

Curtis