cobra marty

Has anyone used them in the past? Any opinions? Thinking about rebuilding my 500EFI into 540EFI 625-650HP.

fireboatpilot

No personal exp. listened to both good and bad stories on here which I think you'll hear about anyone I guess. I use Bandit up in Brick NJ, formerly Kurts. I got exactly what I asked for and was peomised.

CNC

read this thread.....

http://www.offshoreonly.com/forums/b...d-engines.html

stevesxm

while i certainly have no first hand experience with his hardware, the representations that he posted as far as dyno performance vs the actual hard data he supplied as well as any conclusions that a resonable person could draw from his own statements would suggest that you consider another source.

articfriends

iTrader: (1)

http://www.offshoreonly.com/forums/g...ng-guru-s.html
Broke off allen wrench left in rocker nut, oil pump pick up fell off after 6 hours, main cap clearence was any where from too loose to too tight, rear main was burning/turning black, scored crank bearings, several lifters installed backwards, one cylinder left damaged so bad it needed to be sleeved, It was suggested to re-use the ruined cams pictured in post 28. Motors supposedly made "big power" on the dyno although boat was slower than stock, Just quoting what was discussed in the thread I linked.I would not want to "slander" Mr Roccard, just stating facts and re-iterating what was said in Nordic 95's engine disaster , Smitty

Slow Poke

+1

t500hps

No experience with any builders but some buddies helped me do exactly what your asking about. We made (2) 540's out of my 500EFI's and for the money spent I would not recommend doing it with the EFI setup......it restricts airflow.

Here is some info I've collected about them during and after the builds:

6-2-09 Update: (this is a collection of emails/comments I’ve collected over the last 2 years when asked about my motors).

Used Iron Eagle 308 heads with good port work done. Opened up the 500EFI intakes with monoblade TB’s for more airflow (air is still holding these motors back). 9.75 compression, CMI headers, hoping to make 650 HP on the dyno.
FYI: In hindsight, instead of heads I’d spend the money on port working a good set of GM heads.

Most of these parts came from CV Products in NC. 888-481-7239.

-Crank: Scat # 4-454-4250-6135-L
-Rods: Scat # 2-454-6385-2200
-Pistons : SRP Piston # 212161 10CC Dome, 4.5 Bore, 4.25 Crank, 6.385 Rod
-Rings: Speed Pro # R10451 Standard Tension Moly rings
-Oil Pump: Melling # 10778
-Main Bearings: Clevite 77 # MS829H (ended up with something else that was close)
-Rod Bearings: (8) Clevite 77 # CB743H (ended up with something else that was close)
-Cam: Crane, A take off of the 741
Difference is the intake lobe [email protected] instead of the 741 (this things sounds NASTY!!! but idle quality has suffered slightly. Drilling holes in throttle blades has helped significantly)
-Lifters: Crane # 16535-16 Long Travel GM Style
-Timing Set : Rollmaster # CS2095
-Head Gaskets:
Cometic gasket C5333-027
-Oil Pan Gasket: GM # 10106407
-Rear Seal : GM # 10101164
-Bypass Valve : GM # 25161284
Front Main Seal : # Any GM Big Block

*FINAL: Made 630hp, 700tq fully dressed on the dyno at Precision Marine.

cobra marty

Thanks everyone. I appreciate your comments and PM's. I think I will call around some more.