[Johnny99]

My current project is a 65 LeMans convertible that someone built for 1/8 mile racing over 10 years ago. I have some of his time slips and I suppose it went ok for the sled it is . He was running 7.5 at 90 mph in the 1/8th.

The car is still set up the same. There are some unknows at this time (cam, bottom end).

• 72 30 over 455.
• Flat top pistons with 4 valve reliefs
• 87cc Edelbrock round port heads.
• assumed 10:1 compression ratio
• 1.5 Crane roller rockers
• Unknown solid cam
• Torker II manifold.
• 850 QFT double pumper carb
• MSD billet setup with 6a . 6500 rev limiter chip in it
• 2 inch headers
• 3 inch exhaust
• TH 350
• 3500 (or higher) stall convertor
• 4:11 in a Currie 9 inch

Idles at 1000 with about 11" of vacuum.

I knew the car wasn't street-able going into the project but I was hoping the cubic inches would help. They don't. Mostly I believe from the convertor.

I'm looking to turn it into a street only car that I can use on a semi-regular basis during the summer. But a strong street car. A muscle car.

My biggest question has to do with the round port heads. How can I work around them? Can I get this to run string in the 1500-5200 range?

Right now I'm thinking 3:25 (3:40 tops)gears . Though I could keep the 4:11 for this summer. Stock or very mild convertor. Ram Air manifolds, smaller exhaust. Points distributor with a QJ. Cam can be solid or hydraulic that's not a big deal.

Intake. I know I don't need a single plane. Will a factory cast iron manifold match up with the heads? Would the Performer RPM be better?

Or should I just rebuild the '66 389 that's been in the corner of my garage for the past 20 years

[JLMounce]

Do you know if the current cam is a roller or a flat tappet design?

I think you're looking in the right direction. I think realistically, just doing a new cam/torque converter/rear gear combo that suites each other will get you there drivetrain wise. Your compression is probably a bit more like 10.25:1, but that'll run on 91 octane all day, especially if the heads have the modern heart shaped combustion chamber.

For street use, you'll probably want a hydraulic cam, but if you're okay with doing the yearly or bi-yearly checks, you could do a smaller solid as well. Probably personal preference more than anything on that.

Then handle anything chassis and suspension related to get it a bit more street friendly.

My setup is decently mild, but has enough kick to get you in a good amount of trouble if you want to. +.030 455, torker ii, 232/238 on 112 roller cam, about .550" of lift with 1.5 rockers, fitech, th400, b&m holeshot2000, 3.73's.

Go with a 3.08 or 3.23 and it becomes more highway friendly.

[Region Warrior]

Know what rpm range the power band is? 6500 chip guessing mid to high range.
Less convertor and highway gears will not make a happy engine/fun driver.
If need new street tires find out how big circumference can fit in rear. Taller tires can make it closer to 3.70 ratio. May not need to change gears unless lots of highway cruising.

As JL mentioned brake and suspension mods would be my concern for street use.

[Half-Inch Stud]

get a highway gear rearend.

[Steve C.]

If you feel the converter is too loose now keep in mind it will behave different with any cam and/or gear change. A number of factors should be taken into consideration to determine what stall speed is suitable for your project, such as engine-peak torque, the shape of the engine-torque curve, rear end ratio, and cam specs.


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[Johnny99]

Thanks. The engine currently has solid lifters. Power and I’m not sure of as it sits. I don’t really trust the car as I’m still in the process of doing the suspension and brakes. I don’t feel comfortable going fast in a car that was built by someone I don’t know.

I don’t want to tear into the engine until the weather gets a little worse here. On nice days I can still take it out when I need to. That’s why the cam is still unknown.

The only thing I plan on keeping right now is the short block and heads and th350. The cam, converter and 3” exhaust are going. Unless someone suggests differently the Torker II and QFT will be replaced. I think a QJ would be best. Factory cast manifold or Performer RPM? Not sure on that. Ram air manifolds or 1 7/8 headers, leaning towards the manifolds.

Converter I was thinking 2200-2500 stall.


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[Johnny99]

I’d like to build the car to work in the 1500-5000 rpm range


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[64speed]

Nothing wrong with the round port heads. They aren’t something you have to work around, in fact they are what I chose for my street build after much advice from members here.

[Steve C.]

"Nothing wrong with the round port heads."

Agree. It would be nice to know if any and how much work was done to them. That sort of interrelates to this....

"I’d like to build the car to work in the 1500-5000 rpm range"

A 455 based combo with unported 87cc Edelbrock heads, Performer RPM intake, 750-800 cfm carb and a 230-234 degree hydraulic flat tappet cam would be a slam dunk for your goal with a easy 500 hp.





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[highway star]

Originally Posted by Half-Inch Stud

get a highway gear rearend.

This^ I used to race the 1/8th and now changed gears from 4:10 back to 3:23.
Also changed TC from 10" to 11", stall about 2500 now.

[ponyakr]

Originally Posted by Johnny99

I’d like to build the car to work in the 1500-5000 rpm range

You can do that with a Summit 2802 cam & a stock, or almost stock stall 12" converter.

I think they make 3.00 gears for the 9". That'll probably be plenty to make all the tire smoke you could want, on the street, & keep the rpm down, for cruising.

I prefer a Q-jet. But, the T-2 will work OK, with a good 750-780cfm vac secondary Holley or QF.

LOTS of different opinions on how much power a guy should have in a street car, and just how quick it should be, on the track. I'm on the real conservative side, compared to most on this site. I don't think most guys need 500hp for their street car.

[Steve C.]

"I don't think most guys need 500hp for their street car."

Two people could argue for hours about whether a given product or service is a need. Obviously, circumstance and frames of reference are important in this discussion. What one person needs, another person wants. Also, there are a variety of ways to meet a need or a want.

For example, we all need to eat. But does that mean we need to eat a filet mignon with fresh steamed vegetables and a nice glass of white wine? While at first glance it's easy to assume the difference between wants and needs, when you really start getting into it, the differences can be difficult to articulate.

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[Steve C.]

For interest. Go to Wallace Racing Calculators and estimate your current horsepower.

http://www.wallaceracing.com/et-hp-mph-8th.php


Jim Hand's large displacement 473 cid engine idled smoothly, had excellent low rpm response, and rev'd like a very efficient small block engine. Cruising requires very little throttle opening to maintain speed. very streetable. It was about 480 hp. Many in the community feel his car was the epitome of a Pontiac street car.



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[scott70]

Sounds like a mismatch of some parts combo anyways. MPH should be alot better with the parts listed. You could go milder with exhaust,cam,gears,etc and go just as fast.

[ponyakr]

"...Two people could argue for hours about whether a given product or service is a need..."



Very true !

Lots of guys here would not even think of driving around in a street Pontiac that would not run at least down in the 11 sec zone, on a 1/4 mile track.

Some insist on a high lift thumping roller cam.

Then there are some who are satisfied with tire smoking performance similar to what the '60's & early 70's Musclecars had. Most of those cars had less than 400hp, some not much over 300. With street tires, most of those would only run 14's or high 13's, with a few obvious exceptions.

Even with the lower hp engines, some want a fairly quiet exhaust system, a smooth idle, a low cruise rpm, & a smooth shifting auto trans. Some want a lumpy cam, loud exhaust, a manual trans, and enuff rear gear to make burning rubber & rowing the gears more fun.

Not everybody wants the same thing in a car. NOT EVEN CLOSE !

[Steve C.]

Useable street car HP/TQ. At what point is it excessive?

http://forums.maxperformanceinc.com/...d.php?t=748284


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[NeighborsComplaint]

Less cam (230/240 112), carb (750), convertor (2,000-2,500) rear gear (3.08-3.55). Add dual plane intake and small tube headers.

My '71 GTO was similar. 850 Holley DP, T1 intake, 62 heads, Comp 305 Magnum cam, 3500 stall convertor, 4.56 gears. It was streetable but not happy chugging around town on 50/50 race gas/premium.

Car now has 770 Street Avenger, Pro-comp dual plane, 6x -8 heads, Crane 234/242 flat hyd cam, 2500 stall convertor and 3.55 gears. Drives like a normal car with no bad habits other than a little "cammy" under 2,000 RPM.

[Johnny99]

Thanks . This is a lot to think about but it gets me in the ballpark. I'm going to need to tear it down before making a few decisions. That way I can see if the heads/manifold have been worked on (hoping the answer is no) and what cam is currently in there. I've run the calculators but don't know the weight when it was run. If the car is about 3700 the driver could have been anywhere from 150 to 300 realistically. That seems to put it at 440-450 hp.

The Summit 2802 cam gives me a nice base to start with. Maybe Maybe with Rhoades. I certainly don't want to go with anything more radical. Can anyone suggest a good stock sized convertor instead of the 9" in there now?

The rear has to go below 3:40. Looks like the options are 3.40 , 3.25, or 3.00. I think the 3.25's would be a good selection. I couldn't see me on the highway in excess of 65 in this car. And highway cruising would be limited to maybe once a week. I can always tweak the rpm ration with taller tires I suppose . It's got 235/60 15's on it now. Those are just over 26" . Not sure if a taller 70 will fit I'd imagine a 215/70 might work.

If the heads haven't been ported would a factory iron intake work? If not I'll start looking for a Performer RPM .

When I talk about streetable I mean a car I could use everyday in the summer if I wanted to without aggravation while driving. I don't need a 12 second car though high 13's would be nice

[grandam1979]

Hydraulic roller cam, like you said less gear 3.42 or less and a little less stall converter you could have a great street car. I did a engine much like yours last years for my buddy he did dragweeks with it no issues. Average of about 11.20 for the week his car Is over 4000 for that event.

[Steve C.]

NeighborsComplaint comment..... "Less cam (230/240 112)"

Agree as a minimum. How many times have we seen Cliff Ruggles mention that in our performance realm today a good 455 based performance STREET engine with decent cylinder head flow should have at at least 230 degrees intake duration with a hydraulic flat tappet cam. And many here will suggest more.

The Summit 2802 is a tiny cam ! Besides it won't take advantage of the cylinder head flow here in this application.


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