TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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hey guys i am wondering if i got the sportsman heads with the 2.02/1.60 valves and the 67cc chamber what problems woudl i run into? i know i would lose compresion but i am savin up for a 350 swap so i don't wunna buy little heads for now.why do they say not to put 2.02 heads on a 305? also what is valve shrouding?thanks
__________________ 1989 Firebird Formula, (used to be L03)
355
Flat tops (9.5:1)
Vortec heads (Z28 Springs)
PerformerRPM Intake
Holley 750 Double Pumper
Edelbrock Double Roller timing chain
CompCams XE274
MSD 6AL Ignition box
MSD Pro-Billet Dist.
MSD Blaster-3 coil
Mallory afpr
Tremec TKO-600
Hedman longtubes
Accel 8mm wires
Jegster sub frame connectors
3.73 posi 10-bolt
Lakewood LCA
Edelbrock Panhard rod
Spohn Extreme-Duty driveshaft
Hayes performance clutch
ASCD 2" cowl
Lakewood 90/10 drag struts and
Moroso dragsprings
rear v-6 springs
12.70 @ 107 with crappy 2 1/4 y-pipe stock suspention and a bad tune
With the valve right up against the cylinder wall there is no room for any air flow in that region.
Having too much valve can result in lower air flow thru the engine.
Generally you only want the sum of the valve diameters to equal 85% of the bore. thou due to cam selection, folks have found HP above this. And in all out racing you can go above it, but drivibility can suffer in street use.
NJ Speeder, aka Tim, Has Edelbrock performer heads with 2.02" valves and 60ccs.
Quote:
Important Notes:
When using stock rockers on Performer & Performer RPM heads, .100" longer than stock pushrods are required.
Please use Head Bolt Kit #8550 for an easy installation.
S/B Chevy heads may not be used on engines with less than 4" bore (262, 265, 283, 305, 307 c.i.d.) except with cams having less than .450" valve lift.
ok so i can get the sportsman 2.02 heads and i will just have to use the lt1 cam? with them heads and lt1 cam,performer intake,650holley, msd ignition,and a blaster 2 coil i should be well into the 13's right? then i can swap it all over to a 350 except the cam and i will have a low 12 secound car.
i have 2.02/1.6 valves and now im running into some problems. some people say i used valves too big for the block and i have valve shrouding or something. engine shakes and sounds like really loud ticking coming from under the valve covers. dont screw up like i did and get those big valves. go smaller
2.02 valves fit fien onto teh 305. i have been running mine for 3 years now with out any problem. the cam is what creates shhrounding issues, not the valves. any cam that puts the intake valve past .460 total lift will start to get intopt eh grey area of lift, .470 will cause a noticable vacuum loss, and .480 will require a lot of tuning time and a very custom chip.
with the lower compression on the car you will be able to run a lot more timing too, prolly another 4-6 degrees of base and even more total timign at higher rpms.
big heads are good
later
tim
__________________ 91 Camaro RS-LO3,Auto
New Motor Started
3rd Annual East Coast F-Body Nationals - August 16th @ Englishtown
im thinking about going the same route as you...i was wondering the same thing...i still havent decided if i wanna go 350 or not ive been toying with the idea of just supercharging the 305 but i dont know yet
2.02/1.6 valves will fit fine on a 305. I have an early 90s issue of Car Craft where they put Trick Flow 23* heads on a 305 with a .480 lift cam and made like 280 hp. They claim that the bore of the 305 can handle any lift. They showed a pic of the trick flow heads on the 305 from a bore perspective and they fit fine.
ok so if i run the world s/r torquers with the lt1 cam do u think i would have a pretty good combo? also its either get them heads with the lt1 cam and an edelbrock tbi intake with the stock tbi and stock chip or run a better cam, performer intake,holley 650 carb,msd ignition,accel dist., blaster 2 coil,mallory afpr. so wut do u think is the better setup? i am think if i run the carb setup i will make more power because of the bigger cam and ignition and just cause carb makes more power then tbi. the upside to runnin the tbi is i get the good heads but i am restricted on the cam and i don't have access or the money to get a custom chip burned. so wut do u think is the wiser choice and wut do u think i will run better times with? i'm not goin on the well if u do this and that then u will get that cause i am not goin to spend a million dollors. thanks
ok see but i have no way to do custom tuning to the tbi. and why do u think carb is a step in the srong direction? i don't see many top fuel tbi dragsters outs there. tbi just seems like sumthing to get u from here and there not to go fast. well please try to prove me wrong. also i could give a **** about cold weather start ups and all that crap just as long as it starts up its fine with me. i'd rather wait 15 mins in the morn and go fast then get up and go slow lol
how far down can i have the heads milled so i can retain my 9.3:1 compression?
i'm not sure on what the head cc is currently
i should have the casting numbers on friday when i pickup the heads
then i guess i can give you guys the casting numbers and you can tell me my head cc.........?
can i shave my heads AND use thinner head gaskets?
if my compression does go that low, i am going to think about saving some $$$ for that new vortech supercharger
then when i blow my shortblock, i'll buy a bigger, better motor
__________________ 1991 Turquoise Metallic Corvette Coupe with Saddle Tan interior L98/700R4
Greenwood Signature Rear Spoiler
OZ Monte Carlo Rims
Otherwise pretty much stock 48K original miles
GM ASEP graduate
Saturn C-technician