Brian Felts

I have been thinking about a cam change in my 305. I have a LT-4 cam with the 204/210 duration. What would be the outcome if I went to a cam with a 218/224 duration with the same lift.


Brian

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1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

www.geocities.com/feltsb

RW91B4C

Duration affects the rpm band of an engine - at what rpm it will make peak tq and peak hp.
That would be a big cam for a 305 - it should pull to 6000. If its the comp extreme then get it ground on a 112 or 114 LS - it would help out with idle, low-end, and mileage

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91 B4C 305 TPI - SOON TO BE 383
TREMEC 5-SP, STOCK 1-BOLT REAREAND w/342 GEARS, K&N, AIRFOIL
EDELBROCK HEADERS, DUAL CAT TO HOMEMADE Y-PIPE & 3.5" SINGLE PIPE W/ FLOWMASTER, CRANK PULLEY, MSD, FUEL PRESS REG, COWL HOOD, WELD WHEELS
14.1@ 98MPH
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OTHER RIDE
67 CAMARO - STREET CAR, BIG BLOCK, PUMP GAS
350TH w/ATI 10", 12-BOLT w/373 GEARS
10.94@124.13 ON MOTOR - ET-STREETs w/MUFFLERS

RB83L69

In general, a cam with more duration will move the power band up to a higher RPM. In a TBI 305, with that cam you would need a higher stall converter to keep from losing alot of punch off the line. If the lobe separation is the standard 110° for that cam, it will also make the idle quality very poor, which will require a new chip. You can improve the idle by having them custom grind it on 112° or even 114° centers, but that will reduce bottom end torque even more.

Also, that Xtreme 262 is a flat tappet cam. You should use a roller since your existing cam is a roller.

I'd suggest the Comp "302" roller grind... 264HR-12

This one should not require a new chip. Be aware though, it's on the very edge of working for sure with Vortec heads; with gross valve lift above .480", there is a possibility that the retainers will hit the valve guides.

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"So many Mustangs, so little time..."
ICON Motorsports

Brian Felts

Well I was looking at the General motors cam with the 112 lsa. I do have the 2500 stall converter and custom chip for the LT-4 now but I was pattering this motor off of the car craft 305 325hp buildup. The problem is the cam they used has less lift and more duration than the LT-4. I also have the timing chain cover off right now would be a good time.

Thanks
Brian

------------------
1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

www.geocities.com/feltsb

Brian Felts

btt

------------------
1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

www.geocities.com/feltsb