72 LS5

I can't wait to see the pix too! Congrats! Options?

I had one of those 650 spread bore double pumpers for a while on a 350. It was a tough one to tune as the secondaries were so huge, it need a gigantic pump shot to keep it from hesitating when you mash it. It never ran right. I finally went to a square flange Holley. That carb was meant to be a Q-Jet replacement. With the engine off, have a buddy floor it and peer down the carb and see if the secondaries are opening all the way. Could just need linkage adjustment. Or maybe they are opening but the engine can't handle the air flow and its bogging. If your engine is fairly mild, a Q-Jet may run better, give you better mileage, and better performance. If the manifold is drilled for both a spread bore and square flange carb (like most Edelbrocks), then a new Holley square flange may be easier to tune. Just some thoughts......

Roller is the way to go nowadays, esp with today's zinc-less oils. Sure its more money, but worth it. And your neighbors won't call the cops when you are breaking it in! I had a 650 double pumper on my 350 in an 85 Monte, and that was plenty of carb.

I had the same experience as Scott - got the Energy Suspension poly mounts and I don't experience much vibration.

Good stuff there. With either the peanut ports or oval, it should have some solid mid range power. Some guys here have seen big gains going from a vacuum secondary to a double pumper. I know I gained 3 tenths going from a 780 vacuum to 800 dp on my old 454. The big blocks respond well to mechanical secondaries.

Are you sure you don't have the regular oval ports, as the peanut ports were the tiny ports on the truck heads, like the pic on this post: http://www.chevytalk.org/fusionbb/showtopic.php?tid/204866/ I got the 12.9(9999999999999) with a 3.31 gear and mild 2400 converter, and sticky tires. According to my favorite calculator site, I would lose a full second at 6000 ft! Yikes...... http://www.wallaceracing.com/Calculators.htm

That sounds similar to my old 454 with the compression and cam (230 and 540 lift), but I think I was more like 425 hp than 520 - that dyno seems a little on the high side. My best et was 12.9 at 106 at sea level. Is that number with a roller cam and a good set of heads?

Was this motor built for low-end power? What cam, manifold, carb and timing you running? Those 2.73s must be great on the open road!

Years and years ago I went to a GM deep groove alt pulley, and then to a little bit larger Moroso pulley and never had a problem with either with many 6000 + rpms runs. V-belts just look right to me on these old engines. Note: The Moroso pulley can't handle a 700 rpm idle with lights, radio, wipers, and ac on. But my AC is busted and I don't drive in the rain...

That's UNREAL! CONGRATS!!!!

Is your carb a Holley and does it have a choke horn? A drop base with a 3 inch filter may be putting your lid right on the choke horn. I think I'd rather have no spacer and no restriction above the carb than the reverse. Does the spacer have any dyno proven performance increase? I don't think a 2 1/2 filter will give you the breathing a 468 needs. Some say the best drop base is the L88 sold by some Corvette resto companies - it has the deepest drop and best design. Also Wix sells racing filters in 1/4 inch increments for a 14 inch open element. For me, a 4 inch was pushing hood clearance and 3 was a little stubby, so I settled on a 3.75 inch Wix filter with a drop base and Holley with no choke horn on an RPM air gap.

...and I just sold my Strip Dominator last week for 40 bones....

Royce - what have you done to the 502 or is it stock? I'm following this thread as I got a very similar email from Patrick for my near-stock 502.

I wouldn't do it. You are going to spend money on tons of fittings, relay kit, wiring, pressure gauge, regulator, drilling holes in the car, and most of all, your time and the trips back and forth to the store. A mechanical pump on a tame 383 would be fine, in my opinion.

I was in the same boat and wanted to mount it in an inconspicuous location but without cutting any lines. I got some 90 degree aluminum stock, made a bracket, and hung it off the bolt that holds the tank strap on the drivers side. Then I ran the rubber line into the stock hard line. Be sure to put a filter in front of the pump too. Good idea to get a relay switch - Summit sells a relay kit, but you will still need some extra wire (go figure!). I'd go mechanical in a heartbeat if I could, but my block has no mechanical provisioning...bummer.

Neat car! Good luck!

Sorry to steer ya down the wrong path! I haven't had a small block in a while and was just going by what I remembered - things have changed a lot. Please scratch that info about the externally balanced stuff. That's the way they USED to do it! And the 377 is the standard bore stroker, 383 is .030 over - I need a cup of coffee.....

Chances are you have a regular 350 crank - 3.48" stroke. If somebody put a stroker crank in your 350, chances are that it would have to be externally balanced (like the 400s were from the factory). When you use the 400 crank, you need the 400 balancer and flexplate. The balancer is weighted more on one side (of the inside by the hub) and the flexplate has a weight about the size of a pack of gum near the teeth. There are some exceptions such as when somebody has the crank itself balanced with some heavy metal so they can run a regular balancer and flexplate, but that's expensive and not too common.

A 350 with the 3.75 stroke (400 crank) is a 377 with a .030 overbore, or a 383 with .060 overbore. The 400 crank in a 350 became so popular among hot rodders that Chevy finally made their own 383 crate motor a few years ago.

I use this site for calculators - it's great: http://www.wallaceracing.com/Calculators.htm

Update - put the 8.5 pv in and no change. Bumped the primary jets from 80 to 82 - FIXED! The 850 dp now works perfectly all around. Everything on paper pointed to the pv, but the main jet cured the transition problem.

I started reading through this post at work and since it was like a suspence thriller, I had to read the rest at home. Man o man - I don't know if this would kill the ambition for a new hot rodder or Justin should be the number one inspriration for us all! A person can learn more about engine building and drag racing this thread than anywhere. Nice documentation! I wish I took that kind of care putting together my engine. I'll blame it on lack of tools.....

I wish I could pop a wheelie! Great vids!

Thanks David. It's a ZZ4 distributor, I'll check the module.

I've got a second-hand MSD6AL box that I want to throw on. It appears I have to get a kit for HEI that includes an ignition module per some installation instructions I found online. Anybody have tips or advice for this installation? Fairly straightforward? Outside of the rev limiter, do you guys really see any difference with an MSD?