My turn to ask the questions of the Pro's..

[Double Venom]

I have just acquired an E-M rolling chassis with a highly modified late model 460. Not totally updated on the mods to the motor yet, but built by Bischoff Engines out of Indy.

It does have Dove heads, which have been re-worked with "oversized" valves, running a Crane Hydraulic Commander cam. Duration is 236/240.

Carb...that is the question. Mechanical secondary's?
850 CFM or larger?
Double Pumper - I assume yes
Electric choke - manual - none at all? It will be street driven.

Any hints that I should know about before we fire this baby up? I have a lot to learn on these big blocks and I do love to learn.

Oh.. if it were only mine!

Gentlemen, please welcome the latest member and newest Cobra owner to our little site. Jim Peffers, Delaware, Ohio.
Jim is a Viper GTS owner, but now wants to really go fast!

DV -- one more closer to the 300 and one mark!

[Ikestaa]

Welcome to our world Jim!

[Spanky]

Welcome aboard Jim... You're in good hands.

Spanky.

[Jeff Frigo]

The cam seems to be on the small side. Another 15-20 degrees of duration would be more like it. A 850 or 950 Holley HP series carb would be good. Choke not necessary. Have fun!

[Double Venom]

Jeff,

Jim wants his car to dance from corner to corner at idle! The game plan is to have an honest high-9's, or low 10 second car. Think we should up the cam a little, hey?

Think we should go mechanical secondary's. Jim has his "street" car already. Although he does intend to drive it on the street, his only concern is that it barely maintains "streetability!"

Full cam specs:
Lift: intake 325 @ valve 556 rocker ratio 1.71
exhaust 329 @ valve 563

Cam timing @ .0042 intake opens 41.0 BTDC closes 75 ABDC
Duration: 296

exhaust opens 83 BBDC closes37 ATDC Duration 300

Min. RPM range 3000, Max- 6500 Valve float 6500

Cam timing @ .50 intake - opens 13 BTDC closes 43 ABDC Max lift 105 atdc duration 236

exhaust opens 55 BBDC closes 5 ATDC Max lift 115 BTDC duration 240

I'll be calling Bischoff and Crane on Monday to get their specs. Think I'll be pulling the valve covers today and see what type of rockers we've got in their.

Give me more! Got to have more!

DV -- 300 Cobras are NOT enough! Are you registered?

[JRPCobra]

Hello guys, glad to meet you. Oddly enough, I first met Ed because of the Viper. Ed had seen some of my postings on the Viper Club website and saw that I lived relatively close. He wanted to see some of the suspension details on the viper and invited me down to his shop. While he was studying the Viper, I was looking at some of his Cobras and street rods. It was love at first sight - I new that eventually I would have to get one of his Cobras. Well, I finally took the plunge. I have always had the philosophy that if I am going to do something, I am going to do it right. So, Ed and I are going to build the most outrageous Cobra (read: Fast) that we can. When I say that Ed and I are going to build it, I mean just that - I intend to help with every step of the construction except the paint (when it comes to paint, Ed is a true artist - in my wildest dreams, I couldn't come close to what he does). The car will be painted to match my Viper, same paint codes, everything: blue with white stripes. The plans so far are: E-M frame and body, built 460, 4-spd, 9" rear-end, 4-wheel disks, fire suppression, full harness, full cage and halo.
BTW: I may have met some of you last year at the Spring Fling. My wife (Vicki) and I were there doing what we could to assist Ed and were driving the blue Viper.

[Jack21]

$.02.

If this is to be a dual purpose street/drag car, here are some considerations if I were doing this.

Cam? Go a little lighter on the duration, but use a retrofit hydraulic roller cam. Somewhere in the 224I - 234E range. Most common mistake, even with big blocks for the street is too much cam. Won't idle, no power under 3000. You'll hate it. Crane, Comp, and Crower make them. Ford Performance Solutions has a few grinds as well. And use Comp Cams pro-magnum steel roller rockers.

Carb. 800 or 850 DP, electric choke. Demons seem to be favored over Holleys these days. Recent big block shootout in Car Craft used Demon 850's on all engines. Or...Holley 900 ProJection.

Use as much aluminum on motor as you can, heads, intake, water pump to keep front end weight down.

With that much torque, the biggest problem will be hooking it up. Might even consider a C6 auto for quicker times. 17x11 wheels in back to use 335/35ZR17 tires. And Baer 13" front, 12" rear brakes.

[cobrashoch]

Ed- 460's and their derived combos thrive on lift at the camshaft. As a general rule though I generally tell folks not to go past .65 lift figures on 460 street engines with standard or roller rockers. Another thing to look at is the rockers themselves. Are they "Chevy" or truely 385 rockers. It's common that the Chevy stuff is used and thats not cool. Yes, its a good idea to use lots of aluminum on these engines and a 850cfm carb is just about right. My 544 uses a 1050 dominator for example, and as we have discussed previous I like Carters or Edelbrocks for the street. These engines run disproportionally better at lower compession ratios than the other camps. Given the choice of going up or down in compression I ALLWAYS go down. You know the rest of the stuff allready. But keep in mine that it's easy to get these guys to 600 ft.lbs. of torque and I don't like most of the manual trannys out there with these motors. (won't live long with drag race abuse)
I have never used a hdraulic roller so I can't testify there but I second the Comp Cam steel rockers idea if they are made for 385 engines and not Chevy. I'm not in love with the Dove heads generally but with work they are O.K. Ed- I don't know a thing about Bishoff engines here it Indy. First time I have ever heard of them. If you want I can persuit that lack of knowledge as you now have got my nose sniffing. TO BE CONTINUED,,,,,,,,,,,,,,,

P.S- You've just positively got to see my roll bar setup. I will send you photos soon. Unlike any cobra out there. I KNOW you will be interested.
cobrashock

[Double Venom]

Ron,
You know I'm interested! These heads have had some serious porting work on them. Jim & I pulled the Valve covers today. It does have Crane roller rockers. The compression has been determined and punches out at 10.5:1. Cubes come out to 462.2.

Done a little work / research on Bischoff engines. Everything I hear so far is good, but anyone in this situation wants to believe his motor is the best, built by the best, and with the best parts.

If you want to pay a drop in visit, by all means. I have his address now as : 78 Harrison/Brookville Rd., W Harrison, In.
Phone: 637-5933

The tranny is a Top-loader 31 spline, all rebuilt. Looks good. IF the money holds out, I'd like to see a T-56 behnid this motor someday.

Onward...

DV -- I've got the greatest hobby in the world!
Oh ya...we're going to see 300 or more! Are you registered?

[cobrashoch]

Ed- Crane is one of the few companys that make true roller rockers for 385's. When assembled check to make sure the tips of the rockers don't ride to the side of the valve. If they do the little plates below have to be cut and rewelded. You will see what I am talking about. As for the toploader, its a very good choice in my mind till you get to 500 cubes. Then all bets are off. I would expect E.Ts in the high to mid 10's with a 2700 lbs car with the stuff you described. That's fast enough on a 90 inch wheelbase car to my way of thinking. You of course know or have a idea on what has to be done to the rear end of the car to make it work. But the E-M bunch might have some ideas that might be interesting to listen to. I will kind of drop in on that engine shop , maybe this week just to feel them out. As for my roolbars- I will take pictures soon.
cobrashoch

[Double Venom]

Ron,
Ok, terminology that I have lost in the shuttle. You've made reference more than once to the number "385". 385 What?

I will definately check on the rocker clearance. I know exactly what you are referring to there!
DV

[Jeff Frigo]

DV:, Jim, Jack21:

Trust me, for what you want to do, you need more cam. You will never run high nines with the cam you have in there now. I'm surprised that with the amount of porting that has been done that the cam is that small.

I have a 454 stroker FE (DV: 385 series is another name for the 429 / 460's). I know its not a 460, but the size is the same, and within reason, that's what counts. It has a solid lifter cam (hydraulic rollers don't go big enough, and true rollers are hard on the valve train for the street, you have to pull the lifters out every 3,000 miles or so to check the lifters for wear) with 258 / 260 @ .050 duration and .620 / .626 lift. The motor idles at 900 rpm all day long, never gets over 195 degrees even in 95 degree weather, pulls strong from 2,000 rpm, and makes 585 hp @ only 6,000 rpm.

The heads and intake are Edelbrock that have been ported with intake flow numbers of a little over 330 cfm. The carb. is a Holley 950 HP series (double pumper with no choke, warms up in less than 2 minute in 50 degree weather). By the way, this runs on 91 octane (10.8 to 1 comp.) gas.

Guys: I'm not trying to brag, although I am proud of this engine. The trick to getting all of these numbers is the combination of porting and cam. You should give your heads, intake, cam card and comp. ratio to a builder that is very familiar with 460 engines, particularly the heads. Let him evluate what has been done already, tell him what you expect, and let him tell you what else is neeeded.

I'm signed up for DVSPII, be glad to show any non believers.

[Double Venom]

Jeff,
I'm a non believer! I'm a non believer! WOW, we're all non believers! Saturday night you can make us all bow! I will bow the deepest Sir - assuming this old back will let me, or someone volunteers to help me stand back up.

Nothing like a BB, set up right, slamming the gears under full throttle! Man, I can't wait to hear this one run.

Jeff, get on with it. What cam / grind do you suggest, with what little info I have supplied? All Jim wants is to keep it a "little" streetable. Like I said, he has his Viper to play with on the street, but when the Cobra hits the street he wants women to scream and Vettes to run for cover!

DV -- you know...are you registered?

[Jeff Frigo]

DV:

I would love to reccomend a cam, but this depends on the porting of the heads. Numbers around 255 - 265 @ .050 duration and .600 - .650 lift will be about the limit for a high end street engine. The trick is to get the "combination" right for the heads.

[Double Venom]

Damnnn,
don't want to pull the heads off. I do know the valves are stainless and oversized. But oversized to what I don't know!
DV

[Jeff Frigo]

Ed:

Engine builders normally keep all the specs. on the motors that they build including the airflow numbers on the heads if they ported them. You may want to call him and ask.

[dscott]

Ed, A little more info on the heads would be helpful. I like and use the Comp Cams with very good results. The wildest (street cam) they have is a number 34-710-8. This is a roller cam and it needs at least 10:1 compression. The rocker should be a 1.73:1 for optimum lift. The cam specs are 257@50 with 663 lift. Very radical idle. Power range is 3500 up. 850 carb should feed it well. I don't normally use a choke.
Don

[cobrashoch]

Don - Glad you like my camshaft. I had Comp detune it a bit though with HMMMMMM, well you know. Ed, Don has touched on my first thoughts, that you may have too much headwork for that stock displacement engine. Seems the conversation went the way of the camshaft and thats minor in my opinion, simi easy to change. Another concern I have is the rods. 460's have problems there and I hope they are not the stock rods and bolts. I know you will have to drop the pan but a look in there just may save your customer and our future friend untold future grief.
As for the massive headwork issue , if it indeed is overkill the bottom end horsepower will still probably be O.K. for a Cobra . No, make that good for a Cobra. Anyway, Jegs just up the street from you sells Scat cranks of the 4.3 inch variety and that more than anything will wake up those heads. For the price of those cranks they are the bargain of the year.
I haven't had a chance to talk to the engine builder yet here in Indy, but by the way you described those heads I'd bet a $20 bill I know who did the headwork. And yes, they are very, VERY good. If a bit salty in price too.
cobrashoch

[JRPCobra]

Hello Guys - Ed and I pulled the pan today, the crank looks new and the rods appear to be Eagle ESP. The compression ratio is 10.5:1. The intake is an Edelbrock Performer RPM and the carb will be a Holley 850 Double Pumper.

[Mr.Fixit]

A 460 with more duration than 225 @ ..050" needs an 850 dp holley. I don't like demons they are no better than a decently prepped holley. With the cam figures being thrown out there, a 950-1050 cfm carb may be better suited.