Ramjet Cam/TB Swap

[84rzv500r]

Current Cam
Camshaft duration (@.050 in): 224 degree intake / 234 degree exhaust
Camshaft lift (in): .527 intake / .544 exhaust
Camshaft Part Number: 12366543
Camshaft type: Hydraulic roller
Compression ratio: 9.6:1
Throttle body Part Number 17113524
Throttle body: 48mm
Valve size (in): 2.25 intake / 1.88 exhaust; stainless steel

Proposed CAM/TB
.566/.566 lift; 296/302 duration; 110-degree centerline
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=597&sb=0#

BBK Power-Plus Series Throttle Bodies 1536 58mm

And this SW to raise the rev limit to 6200 fix the damn IAC valve hunt cause I dont have a mercruiser i/o drive or automatic bolted to it...
http://www.obd2allinone.com/sc/toplevel.asp?cat=32


I think this should wake things up a bit... prolly sacrifice a bit of that off idle torque for a bit more HP on top... though she is still pullin hard at the 5800 rev limit, it does get a little flat above 4500..

Thoughts?

 

[Bullshark]

Hi Mark Sounds like you have been doing your homework. The TB and cam, in that order are certainly good places to start. The RamJet is choked by that old stock TB and the cam will let you take advantage of it up at the higher RPM's
As you know, I opted to dump the MEFI. Even with the software you point out it will be challenging to say the least to get it tuned properly without an engine dyno. We have that software here at Competition Marine Center if you just want to make a few mail order burns.
I went with the Accel Gen 7 way back when, but today I would go with the Holley HP EFI. You will be much happier and it is cheaper than the pro version of MEFI Burn. Especially if you re-terminate the RamJet Harness with Holley ECU connectors.
Bob

 

[84rzv500r]

wow the holley unit is very capable... Thinking.... only three issues with the ramjet

1. No load IAC hunt/stall at stop (run/decel to idle transition)
2. horribly rich mixture across the board (especially at idle)
3. it lays down above 4500 rpm

other than that it is a hoot... one of the fun things to do is idle along in low gear and slap the throttle and let off.. it will light up the 325's for as long as you like and then return to idle without changing ground speed.. throttle response is instantaneous.. likely an effect of rich mixture and smallish throttle body

I am slowly working the bugs out gonna go back to the drag strip in the spring with my new traction bars....

 

[rtj]

They are kind of pricey, but afr magnum cnc heads apparently really wake up a zz502. Several magazine articles state 700 hp.