1991Z07

Just dropped off my BowTie block at the machinist's to start on the new motor. After studying the sonic tests on the block, his suggestion was to bore it to 4.125" and stroke it to 4" and using 6" rods, giving me a 427...this will be a scream. He suggested a 441 cube was possible, but it isn't quite as nostalgic as a 427.

Since the crank, rods & pistons were going to cost the same anyway I figured "What the hey!". I was just going to make it a straght 400. I'm putting a Mini-ram on this puppy and won't ever look back. Heads will be Brodix Track 1 CNC's. They'll flow 300 CFM and have 220 CC runners. The bottom end is all Crower.

My requirements to him was that it needed to run on pump super, so 11.0:1 compression is the maximum I'm willing to go right now. I'll change the pistons out and bump compression when I feel like I need more power, and I have my Z06 to drive. Then I'll not mind putting $4/gal. race fuel into it.

We'll be doing a completely custom grind on the cam, and there will be a solid-roller with a rev-kit. I'll probably get it back in 4 months or so. Good things take time, and this guy knows how to put motors together.

I'll keep updating on the progress. I'm PUMPED!!!

FoolCrzy

I guess Everything IS bigger in Texas

91-Z07Coupe

AHHHHH!!! NOW I know who took my license plate!!!

That ought to be one FUN ride when you are done with it!

Monty

Joe,

I guarantee you'll love your SBC 427 when you get it. They make amazing power.

I used a Crower 4" billet 4340 Ultralight crank and Crower 6.125" billet 4340 Stroker rods in mine as well. Crower stuff is top notch. Although I have the rev limiter in the SpeedPro SEFI set at 7000, it's good for 8500rpm+.

I was going to use a Miniram too, but was unsure if it would flow enough. I called TPIS and they said they thought it would though. I ended up going with a Hogan's custom aluminum sheetmetal manifold.

I ended up with a 11.27 CR, and have had no troubles. On the dyno it made 650hp at 6700 on straight 92 octane.

I ran you combo through Dyno2000, using the cam I ended up going with. I tried 4 custom Comp mech roller cams on the dyno, and this one, made the best power and torque.



For comparison, here's how the actual dyno results compared to the predicted dyno results for my engine. I'm sure you'll agree they are amazingly close. I'll bet these predictions would be pretty accurate for yours as well.

-----DYNO2000-----SUPERFLOW
RPM---HP---TQ------HP---TQ
2000--164--431

1991Z07

Wow Monty Thanks for the info.

I told my machinist about your graph and, although he isn't a terrific fan of the Dyno2000 software, snorted at me. He's looking at another software package that, according to him, is MUCH more accurate. He said his job is to make anything and everything BEHIND the engine break. If it doesn't, then he's not done his job.

Regardless, even if we are close to your model, it will get me what I wanted. My request was for around 550hp and as much torque as he could get me. Looks like I'll have that and then some!

We're using the enduro crank for reliability since I autocross and road race this car. The rods are the same as yours, Crower Billet Stroker's.

Do you have an exhaust on your car? Do you drive it on the street? I was just wondering what a 427 SBC sounds like? Does it thump you like the BB versions do?

1991Z07

The 355 was always intended as an intermediate motor. It is also going to be the backup if anything happens to the 427. When the racing season starts, I won't have enough time between the weekends (or the wheelbarrows of cash) to have the engine fixed for the following event.

This way I can come home, swap the motor and chip out, and be ready for the next event.

I don't think I'll need any more power after this. I'll have a hard time getting the car to stick as it is. I use 12" Goodyear road-race tires and it still spins them now. Should be a scream down the 1/4 though! [img]http]//www.corvetteforum.cc/ubb/biggrin.gif[/img]

Monty

I was skeptical of Dyno2000 at first, but as you can see it's pretty close. However, I did have to tweak the inputs after I had the actual dyno's done to get Dyno2000's number that close. I had to change the exhaust. Even though I dynoed it with 1 7/8" stepped tube headers, it was more accurate with just large tube headers and open exhaust as the exhaust input. Initially, it said I'd make almost 700hp and 600ft lbs at peak, with a smaller cam than the one I decided to stick with.

My machinist was skeptical too, until he saw how accurate they were. I also have Engine Analyzer Pro, I think it retails for about $400 or so, and although it's inputs are much more sophisticated, it's predictions were almost the same as Dyno2000's.

I'm sure you'll break some stuff when you get that motor installed. I've upgraded the tranny, driveshaft, and differential in anticipation of that. I'm not running slicks, just sticky road race type tires, so I'm hoping it should hold together.

For exhaust I'm running 3" sidepipes, behind chrome reproduction '69 sidepipe covers. Unfortunately, I won't have a set of headers made for another couple of weeks. Since I used a tall deck "rocket block", and 18* heads, you can't get an off the shelf header that will fit in a Corvette chassis. So I have to get a set custom made.

My car is 95% street. Since you're gonna race yours regularly, you could probably go with more cam. I was hesitant to go with such a large cam, but I had to keep telling myself that this is basically a 'big block'in a small block motor. We tried 4 cams on the dyno, and each time we put a bigger cam in, the power and torque kept going up, all the way across the rpm range. The biggest cam, the one in it now, actually made more power all the way across the rom range than the smaller one's did. To me, that means it could take even more cam, but I am satisfied with it's power for now, and just settled on that cam. I can't really tell you how it sounds since the exhaust isn't totally done yet, but on the dyno with headers and mufflers it sounded pretty darned good. Even with a 256/264, .690"/.650", 112LSA cam, it idles smoothly at 850 rpm. It's got some rumble/lope to it, but it's amazingly smooth. And it accelerates like you wouldn't believe. My machinist is one of the best engine builders for the NMCA/NSCA/NMRA 'street legal' guys, his partner was champion a couple of times. Anyway, he said it was "very frisky", meaning how fast the engine revved up. When we had it on the dyno, he kept overshooting the dyno.

Other than the custom manifold and Jesel belt drive, it doesn't look that much different than any other hot small-block. I just tell people it's a 350.

I know you'll love it. The only bad thing is, after having one of these bad boy's under your hood, it's gonna be hard going back to just a 350 or 383. If you ever had too.

Good luck! If you ever have any questions, let me know. I learned alot building that thing.

Chris@SD

Why not do an 18* head with a Vic jr?!?! 650 would be the number to shoot for there.
Either way, you are looking at one hell of a ride! Enjoy.

1991Z07

Thanks Monty! I'll certainly shout if it gets too deep.

My builder does a lot of track motors. As you can see from the signature file, I'm getting ALMOST as much HP and more torque that Lingenfelter's top 383 package with a "littl ol'" 355. Makes one wonder what this would have done as a 383.

It will be a long, uphill run to get it there. Dave's got about 25 motors in the pipe right now. Mine will get done according to the availability of parts. The rods are 6 weeks backorder, but the crank is on its way now. We were a little worried about it, as they were at 12 weeks a little while ago.

I noticed on your web page that you went to steel shafts & Tom's stubs. I'm going to get Tom's to just build me the full-tilt 4.10 Dana 44 and get it over with. They are actually very reasonable, about $2200 complete without exchange.

Monty

Yeah, I've been thinking about having tom's do the whole diff too. I'm just trying to get everything else done first. I'm sure you've seen Merlin522's twin supercharged 522ci project. He got the whole Tom's setup as well. I figure if it can handle 1200+hp/1700+ ft lbs in his car, it ought to handle our 'measly' 600-650hp stuff .

1991Z07

I wanted to keep the injection for the snappy throttle responses, and the Track 1's will do what I want (for a bit less than the 18*'s). Eileen Formato told me that Jim's car (@420CI) ran on pump gas like a bat outta hell, and still got low-20's for fuel mileage.

I can always bump the C/R up a few points, run race fuel and get in the 600 range. I'll get used to this combination first.

Merlin522

Tom's =

http://www.tomsdifferentials.com/