[STROCKER461]

I am currently running a solid Comp. Cam 300b.
I am looking to pick up a tenth in the 1/8 mile. A buddy of mine is lending me this Roller cam to try. What do you think?
Comp. Cam: Grind # PB 4620/1660 SR 110.0 installed @ 106.0 Int.Center Line, Duration @ .020 tappet lift 299-307
valve timing Open Close Open Close
@ .050 INT: 29 BTDC 61 ABDC / Exh: 71 BBDC 23 ATDC Lobe Separation 110.0 Duration @.050 Int. 271 - Exh. 275
Gross valve lift - Int. .648 / Exh. .630 with 1.5 rockers.

I will be installing a S.D. lifter bore brace . I also have 14 brand new Comp 859’s( will have to buy a pair) but they don’t have the oil hole like the new 859’s. If this cam works as expected I will upgrade lifter choice for the next season.

Questions:
1. Which valve springs to use ?
My current installed hgt. is 1.840 according to Butler’s paperwork that came with heads when he did them using Comp’s 741 Retainers & 611 Locks.
2. Will heads need milled to get more compression to help achieve my ET goal?
3. What about using Titanium Retainers with +.100 instead of cutting spring pockets to get more installed height and for more valve spring choice?

Here is my current combo.
1968 Firebird - Race wgt.2945 - Drag Car Only (So far 1/8 mile only)
400/461cu.- Ross pistons ,Eagle Rods, Forged Crank, Assembly balanced.
Plate Honed, Block is poured to half way of front water jacket.
After market 4 bolt main caps (# 2,#3 and # 4)
E-Heads from Butler Perf. 2.19 int / 1.77exh. 5.275 long.
Flow info:
Int. 321 @ .600 lift – 330 @ .700 lift --- Exh. 257 @ .600 lift – 260 @ 700 lift.
Compression? ( flat top pistons are .004 below deck )
Head gaskets - .040 Cometic. 74cc’s
Comp solid cam 300-B -6 .265/.276@.050 = Gross Valve Lift. 602 -.593 - installed 103
106 Lobe Sep.,using 1.65 Comp. rockers. .026 / .028 Valve Lash.
No lifter bore brace.
4500 Flange Victor intake-port matched only.
1100 Dominator from Pro Systems.(Redid by Shaker 455-Jeff)
1/2'' spacer with a 1/8 safety plate. 88 square jets- no P.V.
1 7/8 Maddog Headers with Flowmaster 4-2-1 collectors.
Powerglide with 1.76, transbrake, 8'' A-1 Conv.45-4800 stall ( stall adjusted by TCI )
4.88 Gear, Ladder Bar with coil overs,14x32-15 Slicks. ( May switch to a 4.56 for 2011 season)
Best et so far 6.078 with a 1.28 - 60’ , at 110 mph.( with a 9’’ conv.-not sure of stall )
Timing at 38, leave off 2 step 3700,shift at 6600, 6400 at finish line.

Thanks
Tim

[goquick]

The cam should pick you up to where you want to be and more, but I wonder if you have the valve to piston clearance if you could milled a good .080" off your heads and get there. But do check piston to valve distance!!! I also think 2" primary headers would get you there too. My 408 prefered the 2" primaries over the 1 7/8" type.

[STROCKER461]

Thanks for reply, and yes I am definitely will be checking pistion to valve clearance.

Tim

[STROCKER461]

Anyone else?

[71 Ventura II]

W/ a 1.28 60' I can't see dropping to the 56's would help. Stick with the 88's and build the power in the engine. imho

[Ron H]

I agree with keeping the gear. The roller will like the higher rpm and lower gear ratio.
More compression would definately kick you up.