Just joined, recently bought a 71 z28 from a guy with a 30 over 454, solid roller lunati (685 lift, 0ver 300 adv dur, 110 ls) 10.25 kb pistons, steel crank, 2.25/1.88 valves in 781 oval ports that were done by iselin racing in omaha, crower roller rockers, 4 bar stud girdle, victor jr with a modified 830 holley, 2.25 in hooker headers in to 3 in flowmasters. Car has a super t10 that has hardened shafts and a 12 bolt rear with moser axles and 4.56 gears. Any one on here from omaha? that is where this thing originally was built from the info I got. Its black with some weld wheels and a lightning bolt looking reddish and blue stripe on the bottom. car has supposedly ran a 11.27 on street tires, couldn't have been the ones on it now cause they spin forever. I am waiting for the guy I bought it from to send me the cam info, I read the card and think the numbers I typed are close, could this thing really be making 600 hp like the guy told me?

Welcome, you'll find a lot of helpful people here.
Yea, it could be makin 600hp, if the cam is in the 250-260duration range. What mph did it run, that would give us a better idea of the power its makin. Also do you know the weight?

My brother's 427 made 621hp/555lb-ft on the dyno with the following specs:

049 heads, pocket porting, 2.19 intake valve (very similar to 781's from the factory)
Victor Jr
830 Race Demon RS
GM Steel Crank
12.5:1 JE pistons
Crane Solid roller .714/.714 lift 286/296 advertised.

Considering your cam has more duration and you have more cubic inches to make up for the smaller lift and lower compression, I'd say it's not out of the question. It could be making 600.

Well with my little gps I have seen 116, it could be faster cause it takes the gps a bit to record. I don't know the weight, it has a glass hood, 12gal fuel cell, lite seats, no wheelwells in the front, 4 point cage. With 28in tires it will run about 6600-6800 on the tach, it doesn't have a speedo. I just looked on lunatis site, duration is in the 270 range@.50

What is a safe rpm range for this thing, I have been keeping it around 7000, the guy saidd it was good till 8000, I don't even spin my snow machine that high. I will say this is my first well built big block and I have to think whoever built it (iselin racing) definetaly knew what the heck they were doing. this thing revs like a small block, I know the 4.56 have alot to do with it, but my friend builds and races modified dirt track cars and he was very impressed with his first ride in it.

Well the good news is that its got the potential to make 600hp with the parts listed, (whats the fuel system?) The bad news is its only makin around 450hp if its runnin 116mph, and thats at 3500lbs. One item thats doesnt match the combo are the headers, I'd recommend some 2" headers for it. Also make sure the timing is around 35 total, and the jetting is close, car just may be out of tune, especially if its been sittin.
It better rev to 8000, since its got 456 gears in it, you'll find out the 1st time you try to make it to the end of the 1/4.

Well the speed is probably low and I meant to type 2.18 on the headers, sorry. Well its got a holley electric and runs about 8-9psi. I don't have a track close to me, this info is just from me playing on a 2 lane road that we have always used as a quarter. Kind of redneck, i agree.

Good to 8 grand? Could be, but I wouldn't chance it. If that's a holley blue pump you are talking about, 67RS502 might be right about a fuel starvation problem.

I know it has 4.56 gears, 55 mph is 3100 rpm. I was thinking of puttin some 3.55 in it but since it is just a toy I will probably leave it alone. Still getting used to shifting it, the shift lite never seems to go out. My 97 ws6 t/a didn't rev this fast. The thing is a hoot, starts right up hot or cold, takes some time to idle when cold but when warm it idles at a nice calm 1300. O, it has line loc also, make showing off easier.

Yea, your fuel pump may not be up for the job.

1st post an already crackin jokes about us rednecks ;) tongue.gif
thats the way we do it here too, hit the feeder when no body is around.

I meant I am a redneck for racing on a public road. I don't think I have a fuel problem, I don't think it has any problems at all, it pulls like heck all the way to 7000. Maybe next summer I will get it to an 8th mile track and see what it will run, but first i need to get some better grippers out back, I can blow them away in 3rd, which is fun as hell but not good fer winning races. I have raced my buds amg55 mercedes and smoked him, its is a 5 second 0-60 car and runs a 13.5 at 107 qrt car according to the mags, if his will run that I am at least 1.5 sec quicker even spinning like hell in 2 gears.

found a mph calculator and my combo is good for 125mph at 6970 rpm useing my measured 27.5 od tires. so by my tach I am running around 120 in the qrt, not too bad when i can't stand on it hard till 3rd gear. guess I need to get another set of welds to put some stickies on to find out what it can really do.

Be careful with that. Putting that much power though a super t10 on slicks is kinda risky. I know you've got the hardend shafts, has anything else been done to the trans?

Well I don't really don't know, the guy said it had been beef up and built to take it, whatever that means I don't really know. Shifts really good, goes into gear very positively. Has a hays flywheel and a dualfriction centerforce clutch and a blowproof scattershield. I will never run slicks but was thinking of some sort of street drag tire. This car is more of a drag car than I wanted but once I heard it and rode in it the deal was done. I had a 79 vette with a mild 454 and this thing makes that feel like a dog and I never got beat with the vette. granted, we are talking small town northern iowa, not alot of built cars around here. I forgot how much fun one of these old built cars can be, have had many modern musclecars, but this 71 makes me grin from ear to and and for me thats all that really matters. Well that and women and long burnouts.