Big Cam for TBI

[kyotey1693]

Hey guys,

One of the members of GMT400 recommended your sight. I have already read some pretty interesting things in the short time I have been snooping through the threads. I realize you guys cater more to tuning. I eventually will need a new chip for my truck but right now I am trying to iron out a parts list.

I have an 89 c1500, rcsb, 5.7 tbi (with all the tbi mods), 5spd, long tubes, full exhaust, crane cams ignition and coil, 1.6 roller rockers, open element air cleaner, etc. The usual stuff.

I have a bad lifter and would like to swap cams and would like to throw some better heads on at the same time. The truck is a street truck. It's a daily driver. It is a work truck for me but it's pretty light duty work. I run a pool cleaning business, so, no heavy loads, trailers, etc.

I haven't decided on which cam for sure, I want more performance obviously but I want a lopey idle as well. I plan to stay flat tappet because I doubt my block is tapped for the spider and I don't plan on converting it this time around. I also figured I would go with a regular sbc intake and a tb adapter. So, I have questions...

I am thinking about going with these heads. I have never seen or heard of aluminum vortec castings. Any info or opinions on these? They are 2.02/1.60's. That shouldn't be an issue, should it? One of the other reasons I like them is for the weight savings. I would like to drop some nose weight off the truck. I plan to add one of the Weiand superchargers later down the road. I also want to retain my 1.6 RR's, will they cause and ptv clearance issues with this head combo?

What cam recommendations do you guys have that can increase performance and give me some lope? (I know that is hard to do on one of these engines but I'm willing to sacrifice some of the lower end performance for a little sound) What injectors and fuel pump should I go with?

I realize some of what I have planned may not be the most cost effective in but that's ok. I like where this project is going and I intend to have fun with it. I'm not trying to make a street monster, I just want to make what I have better and more fun. I know many will say to do an ls swap but that is out of the question for the time being. If I had the time, resources, and location, it would have already been done.

[Hog]

The GMPP Fastburn heads have a 210cc intake runner volume and are used on the limitd production ZZ430hp/350cib crate engine and the 425hp ZZ383 crate engines.TRhere is the ETC Edelbrock 180 and 200 cc heads as well.All these heads are Vortec compatible.Oh there is an AFR head that is designed for L31 Vortec 350 use that even has it emisions exemption they are 190cc. peace Hog

[1project2many]

I think you're not going to be happy with the 200cc port as I think a close to stock truck should go a bit smaller. If you ever get around to installing that supercharger you'll have more than enough power to make up for smaller ports.

Vortec Bowtie heads are relatively new but they seem to be a very good performer although they aren't aluminum.

[EagleMark]

There's loads of good cam choices, but the lope is hard to do, EFI hates fluctuating and low MAP. Can do it with Open Loop Idle but it still a hard transition to CL. I think it's the TBI wet intake that makes the varible if idling for one minute the tune wants one thing and if two minutes it want another? I got it to work once but never liked it.

[kyotey1693]

Thanks for the replies. I hear a lot of people say that I will give up a lot of low end torque with the bigger cams. Will I actually be losing it or is it more of just shifting the power band a little higher?

[1project2many]

It's the same meaning. You'll move the powerband higher and give up torque at the bottom. Of course if the cam is too big you'll give up torque all over your rpm range.