i just wanted to get peoples opinion on cam selection I've got a 91 camaro 305 tbi, vortec heads, 1.6 full rollers, I've got .540" lift at the valves to play with. I'm not looking to get some crazy cam, i still have to pass smog

 

I don't know alot about tbi motors, but I'm selling a ZZ4 cam in the classifieds if you are interested. It's a nice improvement over stock on a tpi setup.

 

vortec flow numbers drop off after .500 intake lift so no point getting a high lift cam... get something close to .500 lift in the 230-240 durration range.

 

ya see if you can find some flow bench numbers on those heads, can find lots of stuff just googling chevy head flow, even if your springs will support that kind of lift, there no point in having more lift then where your heads stop flowing, which as is said about me is probably at or around .50

 

the vortec heads dont really decrease in intake flow till about .600 lift however they dont increase at all between .500 and .600 so while not entirely necesarry to go above .500 it may be useful to gain the little extra duration of being open to say .510, .520....

the biggest problem with the vortecs is the exhaust flow... IE no better than any other SBC head... well almost any head...

i am not real sure on how friendly the TBI is with moddest cams but maybe the XR268H10 or something close

 

Ok, WHAT?@?
230-240 duration @.050 on a 305 with TBI injection? Are you kidding?
That will NEVER run right with TBI, let alone pass smog or be anywhere near streetable.

The roller XR260 or XR266 are about right, probably the 114LSA though. This is going to have pretty low compression with those heads, especially if it now has a .040" head gasket set on there.

 

i did say the XR268, didnt i...

 

I think in Roller cam land there is no such cam as the xr268. I thought it went 260, 266, 276, etc. I *think* 268 is only in flat tappet flavor.

 

well,thanks for the feed back, i have acsess to a flow bench, which i was going to use to port them with, i got everything to put this motor together except for a cam, i was going to use the stock cam to check my clearence's then go from there, i dont really know much about tbi, everyones telling me to get rid of it but, i want to see what i can do with it first
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by the way i've had the heads machined .040 and running the felpro .015 gasket

 

what you think of this grind 2020

 

Who makes the 2020? Which cam is that?

 

crane makes it , Hydraulic Roller Tappet, Advertised Duration 256/266, Lift .407/.429,

 

High lift? The ZZ4 is only .474/.510... I don't really think that is high lift for a roller

 

since we have cam guys in here,, maybe some of u can help me.. car in sig.. + im looking to procharge 10+lbs very soon.. which cam?
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sorry here's the sig-

 

Make your own thread 8T9 bandit, your question isn't really related.

That crane cam is WEE. (As Mike Myers would say). The ZZ4 actually sounds pretty good.

 

sorry hedghog,, ive tried making my own threads on this matter, and have gotten almost no responses. i wasnt trying to hyjack the thread, just had a "relevent"?

 

Since you're boosted it's quite a different cam question. Post in the power adders board, those guys have more knowledge about cams for boosted setups. There's on guy on here with a blower on his 305TPI, and he did quite well. Black late model 3rd gen camaro, I forget his name....

 

ok will do, thanx,, i think u may refering to 86z its an 87 z28.. ive seen bone stock lb9's run great boosted 490+hp and tq.. thanx.

 

first now that you mention the flat milling... .040... how many CCs are these heads now? are you running a flattop piston? i think you are at 58cc chaimbers now... what is your static compression

sorry you are right sonix the 268 i was thinking of is only a flat tappet

However there is a 268XFI H13... but it has a bit much in the lift department
with .570/.565

 

they are at about 58cc right now, yes i am running flat tops, as for compression i'm not sure they aren't on a block yet. .570 might be a bit much.

 

with the vortec heads... think spark plug tight... think it is like 30in.lbs

make sure you have the right gaskets... regular SBC intake gaskets will not work...

also... i think that you would get better HP/TQ out of a different cam...
http://store.summitracing.com/partde...8&autoview=sku

peak HP around 6K with 360HP and TQ Peak at about 4500 with 370 FTlbs at the flywheel

making atleast 300 FTLBS from 2000-6500 RPMS

 

As small as that 2020 cam is, it's probably your best bet if you're gonna keep the TBI system on the car. It's probably mild enough to where it stands a good chance of agreeing with the TBI programming. I could pretty much guarantee the ZZ4 cam won't work at all without some prom tuning. Even when it comes to prom tuning, the TBI computers are quite difficult to work with. TPI prom tuning is a piece of cake in comparison. If you want to run a fairly healthy cam, you really need to switch to a carb or TPI. The ZZ4 cam works just fine with the stock TPI programming. Of course if you decide to turn to the darkside (i.e. switch to carb), you can throw any cam you want in there, as long as it'll pass emissions, if that happens to be an issue where you live. A lot of guys seem to talk up the TBI systems, but when you read the posts on the TBI forum, even the "experts" on there seem like they can never quite get their tune right for bigger cams. I'm ditching the TBI on mine in favor of TPI, which is costly, but at least there's a lot of support and help available to get the TPI system tuned for engine mods.

 

The TBI experts realized a long time ago how lacking the stock TBI ECM coding was and changed it. RBob with his EBL and Dimented with his MAF setup. I realized great benifits going to the later model TBI truck PCM. It is a 100x better ECM than what came in the cars. 8192 baud, Electronic Transmission support, much expanded VE/Spark tables, additional routines, and a full PID IAC control.

This is the 305 TBI idling that is in my brothers Camaro (was in my van when it had cast-iron heads and a milder cam).

http://youtube.com/watch?v=6XLXwAXkDHo

 

Hey Fast. Yeah, I was thinking about you, Dimented with his EBL, and Rbob when I typed that last response. I credit you guys for finding good, viable solutions for the TBI system. Me personally, I'll be doing good if I can manage to burn a simple chip for my TPI system. The conversion you did with the OBDII computer and a MAF sensor on a TBI goes wayyyyyy over my head. Lol. I read through a lot of you guys's posts a while back, and my eyes started to cross in utter confusion after the first couple of paragraphs.