383 combo

[tcb3274]

Wanted to get opinions of my set up going into a street/strip chevelle.

Car is a 67 chevelle with a Moser 12 bolt with 4:10 gears and a TH350.

I don't have a converter yet and not sure what is needed there.

Here is my build:

GMPP Sportsman block with splayed caps, built with large tolerances and all forged bottom end with a Comp Star crank, Scat 6" rods, and Probe -12.8 dished pistons. Its a 350 block bored to .030 for a 383. Block was decked to .005 and compression cam out at 10.8 to 1. The heads are Trick Flow 195 heads that have been milled to a smaller combustion chamber of 58 cc's. They were ported by Chad Speier. They flow .288 at .650 lift. The cam I have is a UD Harold profile. Its a solid roller with 288/296 and 255/263 @ .050 for .626/.626 lift on a 109 lsa. Cam card calls for a 102 ICL but, we went with a 104 ICL. Cranking compression is right around 215 psi. The intake is ported Hurricane single plane with a Holley 750 DP on top. Timing was locked out at 36*.

I'm shooting for mid 11's out of the gate, but who knows if it is more like upper 11's.....

Any and all suggustions are appreciated.

[Casper393W]

I would say depending on how much you want to drive it on the street... I would go with a 9" converter 4000-4500 stall.

I have always had great service from Dynamic Racing Transmission's TCT Call and talk to JR (203-315-0138)

I would also say that it should run a bit faster than you think! I say high 10's is possible if everything is right!

Andy

[tcb3274]

WOW. High 10's would be great!! Sounds like I might be underestimating....

[FloydODB]

4000 stahl on the street is gonna suck

[tcb3274]

Why will it suck?

I have driven a 3800 with no problems on the street.

[MadBill]

What will you be using for tires in 'strip' mode?

[rustbucket79]

The choice comes down to many factors such as streetability, percentage of street to strip, around town use or has to travel for 500 miles on the highway, etc.

Converter stall is contingent on several factors. For a given torque converter, a small displacement engine will stall at a low RPM whereas a large displacement engine comparably built will stall at a much higher RPM. Picking a converter without knowing the engine's output (dyno results) is a guess for both the customer and the converter manufacturer.

Off the cuff, 1500 RPM below HP peak is a good starting point for a track car, 2500 to 3000 below peak is decent for something more street oriented. (6500 peak, 3500 converter)

Be honest with yourself, is this more a track car with licence plates, or a street car that might see the track a couple of times a year?

Don't buy a cheap converter, it will only disappoint you or worse yet fail and take out your transmission.

[steve cowan]

sounds like a nice build,good combo and a set of heads from chad is icing on the cake in my opinion,a couple of questions i have.
are you going to use pump gas or a 100 octane race fuel??
i am going to say that 36deg timing is to much for that compression ratio with pumpgas,i have a 383sbc with 10.6:1 with cranking pressure of 200psi,i run 32 total timing and just disassembled motor for inspection and freshen up after 12 months of a fair amount of street and hwy driving and 1-2 shift 2-3 shift up to 7500rpm and 6800 rpm through the lights 11.10 @ 121.5mph @ 3400pounds 255/60/15 drag radial with 4.1:1 rear gear,turbo 400 with 8 inch 5600rpm converter,bigend bearings and piston skirts com out like new and i was kinda surprised but i must of had the tune up somewhere close,my air fuel ratio at the track is run up to 13.5:1 at WOT through out the run.i have run this combo with a 9inch 4000rpm converter the car run 11.4s and changed to the bigger converter ran 11.16 with no other changes in tune up etc,
if you are keen to run to your engines potential i would not run anything smaller than 4500rpm converter,like everyone has said it is all about your expectation and what you are willing to put up with,i am 60mph at 3200rpm on the highway,

[tcb3274]

Mad Bill

Tires are going to start out as MT drag radials...probably 255 60 15's.

Rustbucket79

Plan on getting a custom converter after a dyno run on the motor.

As far as travel is concern the car leans more toward a track car with license plate than a cruiser that goes to the track. The car will never be driven more than 50 miles at a time cruising. Most of my shows will be 30 to 40 mile commute. I plan on going to TNT nights and getting in 25 to 35 runs a year with the car, maybe more.

Steve

As mentioned above, dyno runs will be sent to a converter company and will be getting a good converter.

Im going to get the tune as close to the track tune the best I can via a chassis dyno and then go from there. The heads are not a brand that Chad sells, but he did do some good work to them and what not. I think it will like 34* to 36* total and if I need to I can mix in some 100 octane or 110 and make a cocktail.

Driving with high rpms dont bother me. I can tolerate 3000 rpms at cruise since I dont have long commutes with the car.

[tcb3274]

Keep all suggestions coming on the build.

[tcb3274]

ttt

[tcb3274]

Anyone else want to chime in and make a suggestion or two?

Love to hear any and all opinions on what I have currently.

[groberts101]

From the parts list it sounds stout enough to me too. I would also suggest putting that fatty on as big a diet as is possible. If not then I'd consider upping the converter to around 4,500 or so. And as you said.. just because the flash speed is higher doesn't necessarily mean the car won't move until it finally hits it. Will be a little snotty and tightly wrapped.. but that's just the price you pay with moderately sized motors in bigger cars. Unless you're really light I don;t see 10's, especially with that tire choice, but I'd think low 11's would be cake.

[tcb3274]

groberts101

Yeah, its going to be a snotty engine for sure. If I had to do it over I would of built a 406 or something, but it is what it is.

I agree, a 4500 might be better suited to get the car into the low 11's. The car will have a boxed frame rails and a 8 point cage as well as full interior. If all this slows it down some, no worries, I plan to enjoy the car with all this and do a NOS kit to add.

[kirkwoodken]

Build is similar to my 406: 10:1, AFR210's, same UD Harold roller cam installed at 102, 4400 stall 10" converter, max power at about 64-6600. I'm running an old Bill Thomas modified Rochester F.I.

I built this engine because it is what Duntov wanted for the 1963 Corvette. The bean counters nixed the idea, but in my opinion it would have changed the history of Corvette. I chose a TB-TH400 over a stick because I have bad knees. Old Z/28 launches harder now in high than my original Z did in first. I think you will like your end result. My engine made best torque at 30.5* total timing, 12.9 A/F ratio. I have no explanation for that.

Interesting side note for me: Moving the mixture adjustment on the Rochester F.I. 1/6th of a turn in either direction resulted in a power loss. Fuel curve is very flat. Bob Steigemeier's chassis dyno, St. Charles, MO. Bob called 4 of his friends when I arrived, telling them to come and see the old F.I. because they would probably never see another one.

Bob thought it would make a good sleeper with a couple nitrous spray bars. The stock Rochester F.I. fuel pump will supply enough gas for 900 HP. Enrichment could be supplied with simple solenoid set-up. The Rochester is basicly a Hilborn with the pill size adjusted by intake air flow.

P.S. Since the Rochester operates on vacuum, I picked a cam that I thought would work well with it. Engine idles at 1200 RPM at 10" vacuum. Harold called this cam his "everything cam", and it does suit my purpose.