3rd Gen / L98 Engine Tech 1982 - 1992 Engine Related

Questions about the 5L TPI

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Old Oct 25, 2004 | 05:32 PM
  #1  
BigBad4Door's Avatar
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Questions about the 5L TPI

I'm looking at a car on EBay. White 91 Z28 Vert... Looks awesome.. Thinking about buying it for a weekend car.

My question is... People have been telling me that the 5L TPI is ****. If i throw 210cc AFR heads, Hotcam, Upgraded Valvetrain, Holley Stealthram and a nice set of Hooker's with a Borla. Will it make respectable power? Why do people say the 5L is ****?

Thanks
Old Oct 25, 2004 | 05:59 PM
  #2  
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Re: Questions about the 5L TPI

Because it is easier and cheaper to find parts for a 350. Buy the 305, and upgrade if you are pulling the engine anyways....
Old Oct 25, 2004 | 06:04 PM
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Re: Questions about the 5L TPI

A lot of people dog the 305 because you can make more power for the same money with a 350. TBI also SEVERELY hurt the 305's rep....but really the only thing wrong with the engine is the stock heads and cam. You can still make good power with it with the right parts and if you decide to go 350 in the future most of the parts will swap over.

The 210cc AFR's are probably a little big for a 305, if you can find a set of 195's I think they'd be much better suited. And I'm a huge fan of the StealthRam.
Old Oct 25, 2004 | 06:16 PM
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Re: Questions about the 5L TPI

Originally Posted by TheGreatJ
A lot of people dog the 305 because you can make more power for the same money with a 350. TBI also SEVERELY hurt the 305's rep....but really the only thing wrong with the engine is the stock heads and cam. You can still make good power with it with the right parts and if you decide to go 350 in the future most of the parts will swap over.

The 210cc AFR's are probably a little big for a 305, if you can find a set of 195's I think they'd be much better suited. And I'm a huge fan of the StealthRam.
Thank you for the quick reply's. I was leaning towards the 210's over the 195's because i would like to go F/I in the future.
Old Oct 25, 2004 | 06:56 PM
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Re: Questions about the 5L TPI

there are inherent limitations in the internals of the engine. it's either the bore or stroke (don't recall which) that limit the breathing and higher rpm efficeincy of the engine. that is why the 350 is a better choice.

the other thing is the heads, which have pretty small valves and low flow numbers. which you will be taking care of so it isn't a concern.
Old Oct 26, 2004 | 03:46 PM
  #6  
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Re: Questions about the 5L TPI

If you plan on going for high power levels and throwing thousands of dollars into the car, why bother with the 305 at all? Sure you can make power with the 305, but for the price you'll pay to do it you can build a 350 cheaper, and make much more power with the same or even inferior parts.

2 other things:

1. If you do stick with the 305 stay away from the 210s. Go with the 195s or even the 180s. The 195/180 with the Competition port/valve job will flow on par with the 210s, and still retain a high port velocity, just in case the FI plans fall through.

2. If you plan on going with a strong engine and then add boost, that should end all consideration into building a 305 at all. The 305s stock internals will not handle high boosted HP levels. So why bother replacing everything but the block?
Old Oct 26, 2004 | 04:21 PM
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Re: Questions about the 5L TPI

Also with the AFR 210s on a 305 the valves WILL hit the cylinder wall after about .450 lift. Only a notch in the block will make them work.
Old Oct 26, 2004 | 04:45 PM
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Re: Questions about the 5L TPI

the limitation on the 305 if the bore. It's not the 4" of the 350, and there isn't a safe way to get it there (water jackets). If you get heads get the 195's as they'll suit you with the 305 and if you ever decide to go to a 350. And the Stealth Ram is nice but if I'm mistaken it doesn't fit under a stock 3G Hood. If I'm correct..I'd get the Mini-Ram. Looks and flows on par with ported LT1 units and can make ungodly HP. Good Luck getting into th 3G's though!!

Chris
Old Oct 26, 2004 | 05:08 PM
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Re: Questions about the 5L TPI

If your going to be sticking with the 305 then the only thing in your mind you should be thinking about is how your going to boost it! Do what most of the mustang guys do to there little 302's and throw a supercharger on it, plus the TPI intake with the long runners works better for the 305 then any 350, you will be selling yourself short going with a short runner intake like the mini-ram or stealthram unless you plan on reving to 7000+ rpm's.

Last edited by Tony89GTA; Oct 26, 2004 at 05:11 PM.
Old Oct 26, 2004 | 08:29 PM
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Re: Questions about the 5L TPI

The StealthRam fits the Camaro hood fine, and will fit the Firebird hood if you notch out the bracing on the inside of the hood.

Don't get the MiniRam, it's severely overpriced and doesn't support much more power than a modded LT1 intake. The only time it's worth the cost is if you're running HUGE intake ports and the LT1 ports can't be opened up enough to match the heads.

Why would 210's be any better for fuel injection? It's the same head design, but with larger runners for more flow capacity. At low RPM's this will actually HURT the engine's performance because it will reduce the intake port velocity and therefore reduce the throttle response and torque production of the engine. Plus it will cause clearance issues and cost more to boot.
Old Oct 27, 2004 | 01:17 PM
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Re: Questions about the 5L TPI

Originally Posted by TheGreatJ
Why would 210's be any better for fuel injection?
FI = Forced Induction

- Justin
Old Oct 27, 2004 | 04:46 PM
  #12  
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Re: Questions about the 5L TPI

Originally Posted by TheGreatJ
The StealthRam fits the Camaro hood fine, and will fit the Firebird hood if you notch out the bracing on the inside of the hood.
If you run a 58mm TB, then the top front of the TB will hit the hood. We have this problem on my friends 86 Z28.
Old Oct 27, 2004 | 09:43 PM
  #13  
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Re: Questions about the 5L TPI

Originally Posted by Tru2Chevy
FI = Forced Induction

- Justin

Well that's different then.
Old Oct 27, 2004 | 09:45 PM
  #14  
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Re: Questions about the 5L TPI

Originally Posted by Zepher
If you run a 58mm TB, then the top front of the TB will hit the hood. We have this problem on my friends 86 Z28.
First time I've heard of that problem. Take a 52 and chop the center out and make a monoblade. It'll flow more than a dual 58 anyway....for that matter a 48 converted to monoblade will probably flow about as much as a dual 58.
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