gnx7

iTrader: (28)

A couple questions on a stroker buildup for road racing/daily driver.

I'm going to try to make my current stock '99 LS1 bottom end with Katech rod bolts last thru I'm hoping at least half of the 2006 road race season.... before it fails and am putting together a back up plan for a spare motor.

I already have some Lunati ProMod billet rods I got a smokin deal on, plan on using the '07 Escalade 4.065" bore alum block and now am deciding upon crankshaft stroke length. I have read that a 4" stroke really likes a redline under 7K to last a long time... but I want to have a motor that will rev to the limits of a hydraulic roller cam. Meaning in excess of 7K rpm. I don't want to go solid roller as changing valvesprings and checking lash/clerances every 3-4K miles I have no time for as I do all my own wrenching.

I have a redline right now in my 346ci shortblock of 7200rpm with milled .024" AFR 205's, hardened pushrods, LS6 intake/ported TB, TSP 233/239 112LSA .600/.603" cam, Fidanza alum flywheel, March UD pulley, LS2 Tchain, 1 7/8" headers, true dual 3" with Xpipe all the way back to Magnaflow muffs, 3:90 gears and 2950lbs with driver. It has been in this configuration for about 20K miles with zero hiccups.

I road raced only 5 days last year which equates to about 7 hours of very hard driving and the rest is commuting and a few trips to the drag strip. I race TimeTrial in NASAProRacing which is (4) 20 minute sessions/day and drive the car pretty hard and am surprised it hasn't blown up yet. This a 90% street car daily driver rain/shine and my reasoning for staying hydraulic vs. solid roller.

So I was thinking a 4.065" bore, 3.9" stroke, 6.125" ProMod Billet rods, and custom Wiseco or JE pistons with most likely some AFR 225 heads, FAST 90/90, and cam still TBD. Compression will be for the limit of 91 octane most likely around 11:1 or 11:25:1.

What do you guys think? Safe to 7500rpm? Would I need Morel lifters or just some rebuilt/blueprinted stock hydraulic lifters? Would titanium intake valves be required to reduce stress?

How often would a solid roller cam needs the springs changed?

I'll probably have Ed Curtis design a cam for this sucker.

Your input would be appreciated.....

DONAIMIAN

iTrader: (18)

You left out a dry sump system. I would use nothing less that Ti retainers and hollow stem valves if not Ti valves also. Rememebr, with thoes kind of revs your cutting the life of the motor. You might be better off with the added stroke, and just gearing the car different.

gnx7

iTrader: (28)

The current gear choices for the RX-7 differential are 3:90 or 4:10 so I'm stuck with that and a 285/30/18 tire at all corners.

I have 20K miles on the AFR head combo and rev it to 7K+ RPM daily on a stock LS1 shortblock with upgraded rod bolts. It has titanium retainers and I believe s/s valves that aren't hollow. I know revs kill shortblocks.... but with good components that are balanced I imagine this will allow it to take the punishment for a long time.

I plan to put on an AccuSump. Never a dry sump. I'm not made of $$$.

DONAIMIAN

iTrader: (18)

If you dont plan to run a dry sump, I wouldnt go much past the area of 71/7200. Look to invest in either the titanium or hollow stem valves in order to keep valvetrain stability at extended periods of time at thoes high RPM's. Also, whats you goal for the motor? How many CI are you looking to get, or and how much power are you looking to make. Also, whats you budget.

gnx7

iTrader: (28)

I'm either doing a 405ci setup (3.9" crank) or a 416ci (4" crank) with the Escalade 4.065" bore alum block. I don't mind giving up a few cubes for the motor to be safer to spend some time above 7K.

I spend a short time above 6500rpm.. most of my time is spent in the 4500-6500rpm range doing the TimeTrial racing. This isn't open top end racing like the Silver State challenge.

DONAIMIAN

iTrader: (18)

I would go with the shorter crank to reduce the piston speed. If you feel like spending money you can always go with a shorter aftermarket crank also.

gnx7

iTrader: (28)

anyone else have some input instead of just a blue smurf?

UMIRacing

Why not go with a 4.8L crank and go to 8?????

DONAIMIAN

iTrader: (18)

I looked around a little bit, but couldnt find any info on sizes of the truck cranks. What are the measurements of them?

gnx7

iTrader: (28)

4.8i crank would make my displacement too small. I want the cubes.

3.9" crank would be safer than a 4" crank above 7K and still provide over 400ci.

8K rpm will require valvespring replacement often and will kill a bottom end a heck of a lot quicker than a 7500rpm limit or so. I imagine it would require a solid roller cam for sure which I don't want to go with. Too much maintenance for a street car that masquerades as a race car on the weekends.