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INCREDIBLE 427 SB!


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$15,000 for a 650 hp motor...

You guys have obviously not priced out Marine motors lately. This is a steal! icon_rolleyes.gif

 

But seriously, this is along the same route I want to go with building up a big small block. Of course, I don't think I would need to spend the kind of money he did for the crank, pistons, rods and camshaft. I'd be happy with a hundred less horses at half the cost.

 

-Andy

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Guest MegaShaft_2000

quote:

Originally posted by Andrew Bayley:

$15,000 for a 650 hp motor...

You guys have obviously not priced out Marine motors lately. This is a steal! :

-Andy

 

You can probably get a turbo Buick motor to produce those HP number for a lot less than that.

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Pretty nice & well documented build...except he didnt mention his Piston's Dish.cc's nor his comp.ratio. He did mention his cyl.head combustion chamber's were at 69.3...that should yeild about 14:1 comp.ratio.

 

What I found even more interesting was his graph under the "427 Specifications" link on his VE% indicating that 90+% was only reached at .300 cam lift while all other cam lifts above .300 was below 85% margin; his graph indicates he tested, I believe, three different cyl.heads for his engine.

 

I wanted to mention the VE spec's his graph indicate simply due to the fact that many of us, at times, on this board [think/feel] we or they are running at 95 or 100% VE. This guy spent boocoo's of dollars & he isnt running 100% VE except at low lift.

 

Anyways; I found it interesting & thought I'ld pass it along.

 

Kevin,

(Yea,Still a ,NON-427V8, Inliner"

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Guest Anonymous

Interesting site. I bet those light Z cars, coupled with the power of a V8 must make one fun car. Cool.

 

Anyway, I wanted to clarify a couple of things.

 

The compression ratio is 11.27. I have only run 92 octane pump gas, and have never had any detonation, either audible or detected by the knock sensor.

 

The numbers Kevin mentioned are not Volumetric Efficiency %. The numbers he mentioned are really Exhaust-to-Intake Efficiency, which merely measured how efficient the Exhaust ports are compared to the Intake ports.

 

If you look at the dyno information, you will see the Volumetric Efficiency numbers. Actually the Volumetric Efficiency exceeds 90% from 3800-8000 rpms, peaking at 99% at 5100 rpm, which is peak torque. Alot off effort and modeling was made in designing this motor. Efficiency was a prime consideration, and what drove the decision to use the 18* heads and the custom Hogan's aluminum sheetmetal intake manfifold. The reason the motor makes the power it does, and the reason it makes over 500+ ft lbs from 3000-7000 rpm, is due to efficiency.

 

I only used the Dart CNC ported 18* heads, I tested 4 different custom cams on the dyno, before settling on the final one - a custom Comp Cams mechanical roller with .690"/.650" lift, 256/264 duration , on a 112LSA. Interstingly, comparing the largest cam I tested, the one I stayed with, to the smallest cam I tested, the motor made more power and torque all the way across the rpm range. Meaning that even at low rpms, the larger cam made even more power and torque than the smaller cam. I believe I could probably go up a little larger on the cam maybe to around 260/268 or so and make more power and torque, without losing any low end torque. Also, I'd like to point out that all the dyno tests were made with 1 3/4" headers, which are way too small for a 427 ci motor. I was unable to get my headers amde in time to dyno the motor using them. I am now running custom 2" stepped to 2 1/8" headers, and estimate the motor should probably make about 700hp/600 tq now.

 

I'd also like to point out that the motor idles smoothly at 850 rpm, and pulls 13" of vacuum. Throttle respons eis excellent, and the engine accelerates very quickly.

 

I couldn't imagine how quick a Z car would be with that much power. Assuming your car's weight about 2500 lbs or so, that's a 1 to 4 power to weight ratio. Most performance cars are lucky to ahve a 1 to 8 (or even 10) power to weight ratio.

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Wow, I think you'd turn the Z into a pretzel icon_smile.gif My car is only making 300RWHP last it dynoed but stepping deep into it in 2nd the other day I was doing 50+ in a 25mph zone no problem at all. I think you'd simply smoke the tires with all the power Monte has. Vette's weight more than Zs but he's got plenty of oats there and probably some big brass ones too.

 

Thanks for sharing Monte, much appreciated! Very nice WEB site too...

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Thanks for the clearifications; that engine definately needs to be in my Z! I also aprreciated you putting the prices of your components chosen on your site when you discussed each item being used: Real Numbers, Real Data & Real Dollars...thanks for the trouble.

 

Running on pump gas w/that engine must be sweet!

 

Kevin,

(Yea,Still a "Non 427 SBC" Inliner)

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Cripes, Monty, I can only imagine if you had the proper headers and a cam suited to the size/efficiency of the motor... icon_eek.gif

 

BTW, the earlier 240Zs weigh in at about 2200 to 2300 lbs. for the most part. That would be fun with anything over 300 hp, let alone something even close to the power of your motor. Just sick I tell you.

 

Thanks for the info!!!! icon_smile.gif

 

Davy

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