restrictive lift?
 

I just got a vortec motor from a 99 tahoe and was gonna build the engine using the vortec heads... I read that the heads have a lift restriction..is that true? Does it effect performance and what needs to change to correct the restriction? Thanks to all who chime in

Re: restrictive lift?
 

Yes it is true.

The bottom of the retainer will crash into the top of the valve guide when the valves reach somewhere between about .465" and .480" open. A minor detail, but still. Metal parts don't like it when 2 of them are attempted to be forced to occupy the same space at the same time.

You can (a) keep your total lift below that; (b) machine the guides down, which can be part of also equipping them with decent valve springs; or (c) use the "beehive" springs, which have MUCH thinner retainers that just sort of accidentalyl give more clearance while also being better springs than most.

I'd recommend (c); probably costs less than machine work.

Re: restrictive lift?
 

Ok well option (c) it is...also to keep my TPI setup what would be the best intake base to use? I wanna get 350+ RWHP....SO what parts combos will work best to achieve this? I read some threads o it seem to veer off into other info I don't need or applies to me.

Also what if anything should be ported

Re: restrictive lift?
 

Ok well option (c) it is...also to keep my TPI setup what would be the best intake base to use? I wanna get 350+ RWHP....SO what parts combos will work best to achieve this? I read some threads o it seem to veer off into other info I don't need or applies to me.

Also what if anything should be ported

Re: restrictive lift?
 

350+RWHP and TPI don't go together in the same post, unless nitrous or a blower is involved.

The only TPI intake that will fit Vortec heads is the one you can get from Scoggin-Dickey or Edelbrock. Not a question of "best"; it's the "only", singular. You'll also find that it costs about $400.

Given the inherent limitations of TPI, you may find it more attractive to ditch that, and go with some other intake that doesn't have its sever restrictions. A Holley Stealth Ram would be a cheap replacement and might get you close to 350 RWHP of everything else is really well done; or, the TPIS MiniRam will make BY FAR the most power of anything that's similar to TPI.

Re: restrictive lift?
 

Lol ok didn't know TPIhad such limitations I figure it was the other components that needed changing...ok so if I use the HSR or TPIs does that change anything electronically? Sensors computer etc

Re: restrictive lift?
 

Well, any time you let in more air, you also need to let in more fuel. So yeah, NO MATTER what you do, it isn't going to meet its full potential, without some tuning. That doesn't necessarily mean a hardware change, although given the Stone Age nature of the computers that came in TPI cars (think back to what your desktop PC was like in 1986, which was what TPI stayed with until its demise... I sure as hell wouldn't want to try to post on this message board with what I was typing on back then) might be a hint that you could do better with something newer. Not necessarily necessary, just, better and easier and faster and more user friendly and all that. But that's up to you. You can track down the right PROM burning stuff, and locate some PROMs, and do what people have been doing for 25 years with these things; and probably get by just fine. You'll just have to learn something a bit more like machine language and bit less like clicking a mouse on a screen image.

No particular lump of aluminum is particularly different from any other lump of aluminum in that regard. Change intake = need tuning. Not much to add.

As far as sensors, all of the various intakes have the places to mount them and such as that. Just putting them in won't be a problem. They'll all work the same; MAP will still be MAP, coolant temp will still be coolant temp, etc. Not a problem.

Re: restrictive lift?
 

Ok when you say going with something newer what suggestion would you make? Are you referring to ditching the TPI and go with something more efficient and provides better performance?

Re: restrictive lift?
 

You might want to do a search for "high flowing TPI" on this forum before ditching your TPI. 350rwhp is not unreachable with the right mods. You will however have to get away from the Vortec heads and base to get there. There is no high flowing Vortec TPI base and Vortec heads do not compare favorably with the many other offerings available. Going to conventional heads and TPI gives you many more options such as the First Fuel Injections TPI system which will easily support 450rwhp.

By the way, my TPI has smoked numerous "newer" systems. Including my son's Ram Air LS1 with bolt ons. In fact my IROC is so much faster its almost comical. Hes looking at a tail pipe turbo to out do me. Do not underestimate TPI.

Re: restrictive lift?
 

Ok so where would I. Find such a base or who makes it? Also what heads would perform well with that base?

Re: restrictive lift?
 

Ok so I found that scoggin dickey I believe the name is makes a high flowing base that compliments the vortec heads also accel does also that way I don't have to ditch the TPI system...I assume I will have to do some tuning with the fuel and air mixture.. would I need larger injectors and throttle body? And would siamesing the runners make any gains or take away from low end torque?

Re: restrictive lift?
 

before you spend any money, PM Dyno Don. He probably knows more about the flow rates and potential of various TPI peices than anyone else on this forum. He may save you from wasting your money.

Another thing to remember: Youve stated a HP goal. I dont know where this goal comes from. Is it based on prior experience or from a freind's car or is it just a number that sounds good to you. A big HP number sounds impressive and we all like to boast about how much HP we're making. However, let us remember why we build hotrods and why we drive them. Because its fun.

While you may or may not be able to achieve your goal of 350wrhp with the Vortec setup, you will certainly have fun building it. Porting the heads and base, porting the plenum, selecting a cam, putting it all together. And when youre done your car will be a blast to drive. While TPI may be limited in upper RPM horsepower, where it excels is in producing a long flat torque curve that will impress the h*ll out of others and make your rear end grab the seat when you hit the fun pedal. So keep an open mind and remember its all about having fun.

Re: restrictive lift?
 

Ok I shall do that...well that horsepower goal was something I chose it wasn't based on anything in particular but yes I want a fun car to drive...my toy lol..I thank u for ur time and advice...how do I go about sending a PM to dyno don?

Re: restrictive lift?
 

Find Dyno Don on the members list. Click on his name and the private message option should come up. Have fun my friend.