What camshaft spec for 425 hp

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PG Duster said:
I still have adjustments to make on my carburetor, every now and then it will pop out of the carburetor on the Launch, it got better after I change from the red to the green accelerator pump cam both were in the number 1 position and changed the shooter from a .031 to a .033, when I was at the strip it did pop on one of the passes off idle launch’s. Any suggestions where to go with the carb adjustment?
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I would use the blue pump cam and most likely a 37 squirter. Also, you will most likely need to adjust the accelerator pump arm for the blue cam so it is in the correct position with the throttle closed. You may have to do that with the green cam too, but it’s been so long since I used one I can’t remember. Dan you take a picture of your green cam?
 
Rat Bastid said:
I would use the blue pump cam and most likely a 37 squirter. Also, you will most likely need to adjust the accelerator pump arm for the blue cam so it is in the correct position with the throttle closed. You may have to do that with the green cam too, but it’s been so long since I used one I can’t remember. Dan you take a picture of your green cam?
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PG Duster said:
Ok, that’s important info. I talked to isky cams and a tech person told me for my combination I would need 230-235 duration at .050 and . 515- 525 lift, on a 107 lobe center. And should put me at about 400+ Hp. That would be a custom grind, isky is right here in So Cali.
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I was thinking of a cam at 230*@050. If your heads support more lift, then lift the valve if you can. Since your mostly on the street, It’s not a huge thing FWIW.

PG Duster said:
I have a Holley vacuum secondary carb on it, will I pick some et and mph with a 750 mechanical secondary?your input would be helpful.
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The secondary spring opens or holds closed the butterflies. Grab a spring kit and a quick change kit if you like & start swapping them out. When you bog, fall flat, slow down, you went to far.

Glad to see you made it to the track. I went past Wednesday and got 3 runs, 1 a hot lap. First time with the ride. Very annoyed at that but really annoyed at the OE shifter. It’s basically finished. Can’t shift into anything except N or D. So it was just 2 runs in letting it shift.

I only changed 1 thing. It improved. No more falling on its face out of the hole. There’s always next week! And the week after that, and the week after that, and the …
:lol::thumbsup:

(Shout out to member @mderoy340 for the quick carb adjustment in the lanes.)
 
If you haven’t you should pick up a copy of David Vizards book:

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There’s another similar book often mentioned here, the title escapes me. Breaks down all circuits in depth and when taken step by step along with the help of many here, you can really get things dialed in. The books (and help here) are valuable tools
 
rumblefish360 said:
I was thinking of a cam at 230*@050. If your heads support more lift, then lift the valve if you can. Since your mostly on the street, It’s not a huge thing FWIW.

That’s true, always the next time. I will make a few more outings making adjustments and see what I can get out this combination sense this was my first outing with the car and later choose a cam. Hope you get that shifter sorted out. Are you trying to keep a stock shifter? I like the aftermarket shifters That B&M makes.


The secondary spring opens or holds closed the butterflies. Grab a spring kit and a quick change kit if you like & start swapping them out. When you bog, fall flat, slow down, you went to far.

Glad to see you made it to the track. I went past Wednesday and got 3 runs, 1 a hot lap. First time with the ride. Very annoyed at that but really annoyed at the OE shifter. It’s basically finished. Can’t shift into anything except N or D. So it was just 2 runs in letting it shift.

I only changed 1 thing. It improved. No more falling on its face out of the hole. There’s always next week! And the week after that, and the week after that, and the …
:lol::thumbsup:

(Shout out to member @mderoy340 for the quick carb adjustment in the lanes.)
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run a blue cam, .037 nozzle, hollow screw, and adjust for instant pump shot. #1 hole is for idle less than 1000, over 1000 use #2 position. Pump shot tuning is done by 60' times. You must launch the car consistently to compare times.
My old combo:
Post 11 second small block combos
 
mderoy340 said:
run a blue cam, .037 nozzle, hollow screw, and adjust for instant pump shot. #1 hole is for idle less than 1000, over 1000 use #2 position. Pump shot tuning is done by 60' times. You must launch the car consistently to compare times.
My old combo:
Post 11 second small block combos
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I will give that adjustment a try, will that work with a 30cc pump well?
 
PG Duster said:
I will give that adjustment a try, will that work with a 30cc pump well?
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You can use it as is but be careful not to bottom out the pump using a blue cam. Lock the throttle at WOT and adjust the pump travel to almost full travel.
 
PG Duster said:
Thanks
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That’s why I said you’ll need to modify the accelerator pump arm with the blue cam. From the pictures it looks like you don’t need to do that with the green cam.

With the blue cam you have to make sure the flat on the accelerator pump arm is flat against the flat on the pump cam. Otherwise you are giving up all the lift from the blue cam. And you’ll have to most likely tighten up the adjustment spring.
 
Rat Bastid said:
That’s why I said you’ll need to modify the accelerator pump arm with the blue cam. From the pictures it looks like you don’t need to do that with the green cam.

Ok, I see what you are talking about. Do you mean bending the tab on the lever that touches blue cam? Thank you, and a 50cc pump well is not needed for that set up?


With the blue cam you have to make sure the flat on the accelerator pump arm is flat against the flat on the pump cam. Otherwise you are giving up all the lift from the blue cam. And you’ll have to most likely tighten up the adjustment spring.
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Cams.
Just ordered a custom ground sol roller last week from Comp Cams for a Pontiac. They had a few stock cores in stock, & one with a 4/7 swap. The price was very reasonable, only a small increase on the last one I had done.
 
Bewy said:
Cams.
Just ordered a custom ground sol roller last week from Comp Cams for a Pontiac. They had a few stock cores in stock, & one with a 4/7 swap. The price was very reasonable, only a small increase on the last one I had done.
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What is the estimated time of delivery.
 
First thing I would do is junk that VS carb for a DP, you cannot beat them for the hit off the line. I found that out on my s/strip '71 340 Cuda back in the day. Tried all manner of VS carbs which ran fine on the street but were crap off the hit (3500 stall). There's a starter for 1>2 10ths. When you've got that running as good as you can I would go to an SFT cam, at least a 4200stall verter and I can see low 12's or better depending on your cam choice and chassis. I went from 13.2's@101+ with a 484/284 hyd. 750DP to 12.3's@108 with a DC. .590 sft cam, 850DP and a TA 4200stall with 4.30's/10x28's and thats with stock unported 2.02 heads.
 
PG,
A couple of weeks. A few cams in front of mine. In the past, they have done them in 4-5 days.
 
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