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PorsChev
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Discussion Starter · #1 ·
Im trying to decide how I want to go about some Multi port fuel injection. I have a standalone computer (megasquirt) that I plan on using, but What intake manifold will bolt up to the carbed SBC heads?
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33553&item=7933934873&rd=1
Will this for example?

Better yet, Will the LT1 aluminum heads bolt on to the standard small block chevy?
http://cgi.ebay.com/ebaymotors/ws/e...&rd=1&item=7932249323&ssPageName=STRK:MEWA:IT
Like this...

My point..

I want Aluminum heads in the future, and I want MPFI...

And no I dont have thousands of dollars to spend. These auctions are about what I'd be willing to spend....

Thanks

Andrew
 

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You cannot use the LT1 heads on a standard sbc due to them being reverse flow cooled. I can't remember what years they were made but GM used aluminum heads on the late 80's vettes that flowed fairly decent. I belive the L98 TPI vettes used these heads. If you plan on buying the TPI unit that you linked I would make sure it was from 350 so you get the bigger injectors. Also the TPI units are known for kinda falling on their faces above 5000 rpm. Just something to keep in mind.

The Wolf
 

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Yes, stock TPI's lose power drastically after 4900 RPM or so. This can be fixed with aftermarket runners and base manifold.

Any TPI made in 87 or later is going to need to be machined to fit the older style heads . . . the ones you probably have. Not too big of deal but if you could find an 85 (or preferebly 86) it would be ideal. The 85's used a hefty relay for the MAF which they later split into two normal size (and cost) relays. They also changed the computer a bit.

If your going to use and LT1, find a whole LT1 block to start with. They aren't that hard to find as they came in a number of cars. They used Hydrualic cams and to convert your older block to use these would probabaly cost more than just buying an LT1 engine.

If you have the computer, look at a MiniRam (very spendy though) or a Stealth Ram from Holley. Then buy the injectors and sensors seperately and piece it together. This will give your powerband a jump up past the 5500 range.

I am currently doing just that. Dropping on some Trickflow heads and the swapping my current stock TPI to a stealthram manifold. I'll be sure and let you know how it works out.
 

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PorsChev
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Discussion Starter · #4 ·
The wolf.

I dont know if this makes any difference. but since you said reverse flow, I'll say that im running an external waterpump. It is in a mid engined porsche...

By reverse cooled, you mean that the LT1 heads just plain wont fit/match the normal sbc waterjackets, or.....

I will be tuning them from scratch, and building it to rev fairly high. What is the problem with the LT1's with why they fall on their face? Bad flow from the intake manifold? Small T/B? Improperly tuned computer?

I really dont want to get rid of my engine, I just rebuilt it, (350 with .030 overbore... I have smog heads, with corvette heads in the backyard, along with a performer rpm intake, holley 650, and headers awaiting to be put on...) But I want the reliability of FI and the ability to tune it for when/if I put on a turbocharger.

Thanks
Andrew
 

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The heads are designed for use on the LT1 block only. Reverse flow cooled meaning the heads are cooled first then the rest of the engine, which is why LT1's run 10.5 to1 compression from the factory. You would have to get the block to match the heads. You can get a complete cast iron head LT1 off ebay for around a grand or so. I think you misunderstood me about them falling on their faces. It's the L98 Tuned Port Injection(pre 91 vettes and pre 93 Z28's) motors that will fall on their faces between 4800 and 5000 rpm due to the runner design. If you want the performance and reliability of EFI, get a complete LT1 and do the swap. You would be amazed at the difference. I swapped in a 350( Tuned Port injected) in my 86 IROC Z. I did a lot of work to it including cam injectors, head work, exhaust, gears, computer modes and a whole slew of other crap. I was never able to over come the short comings of the TPI set up. When I bought my 94 Z28 the stock LT1 kicked the holy crap out of the IROC. IT was like night and day!!!!! The LT1's are capable of 400 HP with a cam change, exhaust and computer tuning without sacrificing reliability. Hope this helps you out. Later

The Wolf
 

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Larger volume intake and runners will help fix the RPM drop off. TPI's actually have a higher potential for lowend-midrange power due to their runner design they just need more volume. The TPI's were designed with a 305 in mind.

If you are looking for a higher RPM FI setup check into a Miniram or stealth ram like I said. Buy a TPI off ebay . .strip the sensors and injectors and drop them onto the stealthram. THen sell the Plenum, runners and intake from the older TPI.

The stock TPI's are VERY capable for 400 hp.
 

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PorsChev
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Discussion Starter · #7 ·
Ok, So let me try and get this straight.
LT1 heads will NOT fit.

But what about the intake manifold/TPI setup...

Actually, I have a friend with a 92 camero... It does not have TPI, but instead it has TBI.... why would this be?
 

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Andrew,

If you want to use the stock stuff, the 85-86 would be a good choice. Since you are planning on megasquirt the computer does not much matter. I would also look into going speed density instead of MAF. You will need to for megasquirt, if memory serves, and it is much better anyway. Megasquirt has onboard MAP and the IAT sensor can be installed in the plenium easily enough.

That said, You might try to find an edelbrock or holley system used on ebay. I got mine for $1200 complete with CPU and converted over to Genboard which was not too hard. Megasquirt would be much easier since it is much simpler. If you decide to go with the OE TPI setup, just bolt it on and learn to tune it first off. Chances are it will make more power than your current setup since you can more properly tune it. Then if you want more power, you can do some porting and and add aftermarket parts down the road. It is not like the factory unit is going to be a dog and will likely be perfect from what I remember of your engine.

Chris
 

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PorsChev
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Discussion Starter · #9 · (Edited)

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You will have to have the manifold base machined for the older style heads as this manifold is designed for post 87 heads. No biggie . . . any machine shop should be able to do it.
 
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