gnx7

iTrader: (28)

Here's the proposed Setup: 441ci
ERL 5.3 with 4.190" bore
4" crank, 6.125" rods (need to buy both)
Dailey billet dry sump
AllPro LS7 heads 2.20" tit valves 430cfm
Solid roller cam (specs tbd)
Jesel solid link bar lifters, Jesel rockers
AllPro LS7 intake CnC matched (maybe run a FAST102)
TB size (to be determined)

This is going in a 2750lb RX7 road race oriented setup, 3.73s, T56 Magnum.

What is a safe redline RPM for a combo like this?

I don't want to go thru the hassle of a solid roller and not be able to spin this to 8-8500 if needed.
It's already set up for a solid roller so it's staying that way. I'd rather run a slightly shorter stroke to gain RPMs. The Magnum beyond about 8300RPM doesn't shift well as per my Mustang buddy with a built Coyote motor.

Thoughts? Input?

SHovV

iTrader: (1)

I see no reason at all why that wouldn't easily run up to 8500 assuming the all the solid roller stuff is set up correctly! Sounds like a wicked *** build! What are you expecting power wise?

lil john

Now you Talkin... Rockers and springs will make it work... the other stuff you got... as long as it got oil run the hell out it... @ RPM is the ?
FAST intake vs All Pro intake - peak TQ vs Peak HP.
That much RPM could pull up past 900hp N/A.

lil john

Also on the trans get in touch with some1 like RPM trans and see what other options you got as far as gearing your ratio 2 match the 8500 rpm... Also 3.73 are great but how well do you think 3.91 or 3.89 max ... spec the new Z/28 gearing...your Power 2 Wt. ratio are well past that of the new Z now your back 2 setting the ratio to pull you out the corner with the ability 2 rev to 8500.

mebuildit

You can run 8500rpm with the AllPro intake, I think that the FAST will hurt your airflow.

gnx7

iTrader: (28)

It has a 3.27" stroke in it right now (360ci) and revs to 10k. Ex-Bonneville salt flats motor... But I want it to last longer so bring the revs down.... Also don't want a dog box and keeping the T56 Magnum as it will see some street duty. As much as possible.

Add torque with 80 more cubes is my goal too. I'm limited to a 27" tall tire and have a DPI Platinum LSD already setup for the diff. Most likely only run a 26" tall road race slick.

Should I run the 4" stroke or a 3.9"? Will piston speed be too high at 8500? The motor needs pistons so I may as well change out the crank/rods and add the cubes.

I'd love to see 700rwhp. My last motor was 520rwhp/485rwtq and went 111mph 1/8 and 138mph 1/4. 150mph in the 1/4 is a goal.

12:1 compression with e85

SHovV

iTrader: (1)

Piston speed at 8500 rpm is 5843.75 with the 4.125 stroke. @ 4.0 stroke its 5666. @ 3.9 stroke its 5525. I'd talk to the piston manufacture about safe piston speeds.

And I'd run more compression with E85. People regularly run 13.5+ on E85

427zm

iTrader: (9)

If it was me, I'd shorten the stroke 3.9( slowing down piston speed), compress it to 13:1+ (since you're running E85), and spin it to 8500. Hopefully Jbzdel will pop in here on this build. He's running a stock bottom LS7 solid roller setup making 680+ on 91 pump.

SHovV

iTrader: (1)

He only "occasionally" spins it to 7800 according to his threads though.

FWIW, SAM build a 454 LSX w/ 4.125 stroke crank and spun it to 9k. It was in their red Camaro and made a little over 1k hp NA.

v8pwr

iTrader: (19)

The 4" stroke is fine you just need good parts all the way around. You already have most of it. The FAST 102 is not an option as it cannot support that displacement anywhere near those rpms. I'm pushing it with a 416 @ 7500. The intake was never intended for that. I'd look @ single plane matched to your heads. If you buy the right stuff and it's put together properly you should make a lot more than 700rwhp.

SSSTANG#1

iTrader: (14)

John B

iTrader: (10)

What did you use for exhaust valve material? If it is Ti intake and Ti exhaust with a well balanced 4" crank, rods and pistons and good valve springs I would hesitate to see 9K!

A.R. Shale Targa

iTrader: (2)

@ 10,000 rpms a 3.27 stroke engine has 363 feet-4 inches of linear ring travel per second. A four inch stroke engine would equal that number at 8175 rpms.
If 8500 is your magical desire then I'd back it down to either 3.75 or 3.9 stroke in order to gain more reliability.

John B

iTrader: (10)

Here's the spec's for Livernois's 8500RPM 4" stroke 427 LSX:

• Engine Type: LSX Series, Gen IV, small block V8, (fully prepped, honed, bored)
• Displacement: 427 cubic inches
• Bore X Stroke: 4.125″ x 4.000″
• Block: LSX Block with ARP main studs
• Crankshaft: Callies Pro-Billet crankshaft
• Connecting Rods: GRP aluminum rod
• Pistons: Custom built forged Diamond pistons (Livernois proprietary, not available off the shelf ) .220 wall H-13 wristpins, heat coating & skirt coating
• Rings: Total Seal stainless rings
• Bearings: Clevite Tri-Armor coated rod & main bearings
• Camshaft type: LSM custom camshaft
• Lifters: COMP Cams roller lifters
• Harmonic balancer: ATI balancer
• Reluctor wheel: 58X
• Max RPM: 8500 rpm
• Intake manifold: GM LSX Drag Race
• Fuel: C16 Race Fuel
• Cylinder heads - GM LSx Drag Race CNC Ported Heads, 11 degree aluminum, six-bolt with fully CNC’d 313 cc intake and 116 cc exhaust runners and 50cc fully CNC’d chambers
• Flow: Intake 430 CFM @ .800 / Exhaust 260 CFM @ .800
• Valves: Ferrea
• Valve size: 2.250” intake / 1.625” exhaust
• Rocker Arms: T&D shaft rocker system with Trend pushrods
• Compression Ratio: 9.1:1
• Cometic Head Gaskets

lil john

John has what is needed 2 get 700rwhp .... you just want more rpm. The valvetrain is the key & correct springs. I went with the Nextek .800 lift hyd. part# 221421 because of my 1.324 od and PAC don't have anything this size 1.55 od +.
You got everything else.. dry-sump / good heads / valvle-train.....etc put the cam and springs in... gear it & kill'em.
POWER 2 WT. ratio would be on par with a hyper-car.....not a super car big difference ... think about the Mclaren P1 9.8 qrt. mile 1.1 million. Hell Tim could beat the BRITS with 1hand and soggy launch.

John B

iTrader: (10)

lil John, guess what I found on PAC's website!!!

v8pwr

iTrader: (19)

I'm using PAC 1530 which is a drop in spring as well. There isn't a lot of options at the smaller diameters but they exist. The springs are similar but the 1530 is designed for a little more installed height and has lower pressures. I don't need that much pressure for what I'm doing. The manifold pic above is what would be needed on this build.

Jenson

iTrader: (32)

From what I remember there isnt enough hood clearance on an FD swap for the Mast intake. You might have to go with a marcella unless shortening the runners on the LSXr-T would do the trick...Or just cut a big hole in the hood.

I have a very similar build in my mind, the boost bug has bit me hard though. Are you planning on ally or steel connecting rods?

Ari G

iTrader: (25)

Nice build but i would stick with a smaller bore size 4.165-4.185 so you can have normal shelf parts and refreshen it a couple of times and stroke it more for lower rpm go power in slower turns

You can have 4.25" stroke and spin it way up there its not about the stroke length but head volume and variations in pressure demands on the heads by bigger diffrence in avg and peak piston speed with the longer stoke

Hollow stem steel valves would be a better pick for strenght and reliability over Titanium valves

lil john

That's Y I love John and Tim etc... but that is alot of spring press. I like the the 640 range like yourself, to go with the stud mount Comp 1.8 rocker.... Trickflow rocker girdle kit is on the way. My man who runs the shop where I get my parts @ flat rate, sent the heads 2 Chris Frank on Sat. He orders & ships 4 me... It is great 2 have a good team.