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Discussion Starter · #341 ·
All bushings and ball joints ordered. Should be ready for arm drop airport race on the 7th.
 

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Discussion Starter · #342 ·
Looks like open carb spacer is the go to with the Air Gap intake. I’ve got room for about 1/2” only. This will help clean up the topside of the engine and remove doubt about whether or not I’m spraying.

 

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1971 Chevelle. Carb’d 6.0 LS Th350 3.90 12 Bolt. 1972 Greenbrier Wagon 489, 700r4 3,73 12 bolt
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Looks like open carb spacer is the go to with the Air Gap intake. I’ve got room for about 1/2” only. This will help clean up the topside of the engine and remove doubt about whether or not I’m spraying.

Now we are talking. Open spacers are lots of fun.
 

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JMHO, but I find it hard to believe that there is any internal difference in the runners of the Performer RPM and RPM air gap.
I think Hot Rod gives the air gap a slight edge due to Edelbrock's advertising $$$. I would probably do the same.
 

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1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
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We dynoed my 489 with a 1" open alum spacer but once installed I had to remove it for hood clearance, I called the dyno/engine shop owner and asked what it was worth? he said about 20 hp/tq
 

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1971 Chevelle. Carb’d 6.0 LS Th350 3.90 12 Bolt. 1972 Greenbrier Wagon 489, 700r4 3,73 12 bolt
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3,255 Posts
We dynoed my 489 with a 1" open alum spacer but once installed I had to remove it for hood clearance, I called the dyno/engine shop owner and asked what it was worth? he said about 20 hp/tq
My half inch open spacer is worth 150hp at the moment. :)
 

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Discussion Starter · #347 ·
My half inch open spacer is worth 150hp at the moment. :)
I’m conservative, mine was only worth 100 hp. Could’ve been worth whatever the RPM kit was rated for, but not on this engine, there’s no need - the power is there all the time!
 

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1971 Chevelle. Carb’d 6.0 LS Th350 3.90 12 Bolt. 1972 Greenbrier Wagon 489, 700r4 3,73 12 bolt
Joined
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3,255 Posts
I’m conservative, mine was only worth 100 hp. Could’ve been worth whatever the RPM kit was rated for, but not on this engine, there’s no need - the power is there all the time!
I think those were up to 250 like my Cheater plate.

The bottom end in mine is ready for spray..if and when I decide to do so. Want to get a bigger kit for the Chevelle at some point, then move the Cheater kit over to the wagon.

Just want to drive the wagon for now. Only moved about 5 feet so far...working on the timing now. The hei crapped out, so put the Pertronix in this affernoon. More adjustable.

How much timing you have in yours?
 

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Discussion Starter · #349 ·
I think those were up to 250 like my Cheater plate.

The bottom end in mine is ready for spray..if and when I decide to do so. Want to get a bigger kit for the Chevelle at some point, then move the Cheater kit over to the wagon.

Just want to drive the wagon for now. Only moved about 5 feet so far...working on the timing now. The hei crapped out, so put the Pertronix in this affernoon. More adjustable.

How much timing you have in yours?
35 total. The advance on my HEI is doing the same thing as yours. I’ll see if it will free up but I’m looking at alternatives.
 

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Good thing about a Pertronix ign. is that it fits in the old style distributor that is much easier to tune and make a lock out for drag racing IMO.
 

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1971 Chevelle. Carb’d 6.0 LS Th350 3.90 12 Bolt. 1972 Greenbrier Wagon 489, 700r4 3,73 12 bolt
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35 total. The advance on my HEI is doing the same thing as yours. I’ll see if it will free up but I’m looking at alternatives.
This one was in the car when I got it. Pretty sure it is one of those $50 cheapies, had a red cap and rotor. Should have kept the rotor, sure seems like it was bigger than the new one. Pretty sure it is making the weights stick open. They are too big anyway, so I don’t mind not using it.
 

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1971 Chevelle. Carb’d 6.0 LS Th350 3.90 12 Bolt. 1972 Greenbrier Wagon 489, 700r4 3,73 12 bolt
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3,255 Posts
Good thing about a Pertronix ign. is that it fits in the old style distributor that is much easier to tune and make a lock out for drag racing IMO.
Mine is their billet distributor. They are easy to curve and it fits in the engine compartment. Looks more old school too.
For locked out I have a later small cap hei for a computer setup, no advance whatsoever inside it. Used it with the msd 6530 controlling the timing / nitrous retards etc…works great and they used to be cheap. Also have a MSD Billet locked out distributor.
 

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Your Chevelle gives me hope that running well into the 11s on street tires with a mild gear is doable. You have a few advantages though; converter (4K) and gear (3.31) jump out as major differences. You have a better intake (square port) and carb arrangement (Holley), too. I’m also thinking you’re slightly lighter (3925) going down the track as well.

You’re probably several tenths slow running exhaust manifolds compared to headers, and obviously, I’ll have that same challenge soon enough.

Are these things enough to keep me out of the 11s? I don’t know...but we will see soon enough.
Did you post the dyno of this engine in this thread?
I skimmed through but didnt see it if you did .
Quite a long book here lol
What is the cam in this engine ?
 

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Discussion Starter · #354 · (Edited)
Did you post the dyno of this engine in this thread?
I skimmed through but didnt see it if you did .
Quite a long book here lol
What is the cam in this engine ?
Here you go.

F6CB3FA1-C43A-47F3-848B-905B24E519E4.jpeg

The cam is an Isky HR 275/284, 228/238, ground on 111 LSA (to smooth the idle and spread the power to work better with heavy car, 2.56 gear and stock converter). The cam was installed straight up at ICL of 109 (+2 built in).

The low lift flow on the intake valves is better than factory, but not great by Mark’s standards. I’d say this is just one area where his engine will shine compared to mine. His outstanding low lift flow allows a seemingly under-cammed engine make huge power.
5F051868-BA83-440A-84D5-CEFA9501B755.jpeg

Still, I feel that I did decent job on this build (especially considering all my crazy ideas), but I’m not a skilled and experienced builder by any stretch of the imagination. Mark’s engine could easily put up 75-100 hp more than mine, using a cam that’s within a couple degrees, if 100 hp is the goal.

Ultimately, improving ET is the goal, as well as looking near stock or retro. With the way I’m running my car, the ET battle will be won in the first 330’. To win this battle, I need torque to overcome the gear and lack of converter, and the ability to apply it to the ground from near idle. The current 116.45 mph (at 4275 lbs) is decent, and sorted out with good air, it might see 119 at 4100 lbs. Do the math with another 50-100 hp, and even more torque, this car might hit mid-11s in the right conditions.

With the long first first gear, my 51 year old car accelerates like a Dodge Viper (the first gear change occurs after 60 mph). Believe me, I’m smiling and enjoying the conversations.
 

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1971 Chevelle. Carb’d 6.0 LS Th350 3.90 12 Bolt. 1972 Greenbrier Wagon 489, 700r4 3,73 12 bolt
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Discussion Starter · #359 ·
After August 7th, looks like the next race will be Monday, August 23, Hot Rod Power Tour at Norwalk. Not sure how many passes or how well they’ll prep the track, but hopefully we’ll log the first 11-second pass there.

I’ll have four new 225/70-15 Cooper Cobras (black wall out of course). I also picked up a couple aluminum drums - but won’t switch them out until I have a couple solid baselines. Electric fan is tempting but I want a more stock appearance.
 
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