I tried this same basic question on another board and thought it might work better here. It's not exactly the same question.

I'm restomoding a '67 junker in a very retro style. We're considering dressing this LS7 out like an L88. I'll need to change the valve covers, change the intake to allow the air to come in from the top like a carburetor, and will almost certainly have to change the throttle body as all of the top mount EFI intakes have a square attachment point and the LS7 throttle body is round. We'll then top it off with a reproduction L88 air cleaner and the under the hood fiberglass piece that creates the L88 hood. All of these individual parts exist, but I'm still working on getting them all to work together on the same engine. So the questions:

-if I have to change throttle bodies, will the current EFI control system on the car be able to control the new throttle body or am I looking at a new electronics system?

-There MAY be an adaptor that can attach the round throttle body to the square intake, but that'll take a throttle body that normally sits vertically and change it to horizontal. Will it still work with that position change? If it could work horizontally, can I assume that the native electronics will run the whole system?

-I've been told about the LS7 valve issues. Are there any other issues I need to know about that I need to get fixed as soon as possible?

-Edelbrock seems to make most of these parts but I can't find any confirmation that they can be combined to make it all work. Are there any other companies that can be suggested as a source for this project?

I know these are pretty specialized questions, but if anybody can help with any part of the answer, I'd appreciate whatever you've got.

 

Should work fine horizontally

Define "current EFI control system". What controller are you using? What kit did it come in or what car did it come out of?

 

Thanks for the reply. We bought the engine through GMPP and got the GM control system that they sell for the engine. I can get more specifics, but that's all I know for now. Assuming that the throttle body will work well horizontally, in my opinion, the same controller should run it. Then all I need is some sort of adapter to attach the round throttle body to the square intake. Edelbrock makes one that will adapt them, but it's an elbow. I need a straight one, preferably not too tall to save space.

 

Why? I don't understand why someone would spend $13k on a modern performance engine that's nothing like a SBC and try to make it looks like one? The money would be better spent on an L88 engine with the latest goodies and it will look correct not to mention be ridiculously cheaper. Your best best would be to either convert the engine to a carb or run a Holley EFI that replaces a carb. However the LS7 still has coil harness packs and no distributer

 

I'm not trying make it look "just like" an L88, just like I'm not using 1967 paint or seats or suspension, etc. It's a restomod. It's totally free form. It's a throwback look. A LS7 is a much better engine. I see no reason to put a carb on it or change EFI systems. Why not just use the EFI system I already own? As to coil harness packs, I've seen numerous ways to move the coils to the front or the back and then drape the wires to where they need to go. Cost is not the biggest concern on a car like this. Getting what you want is.

 

You said yourself you want the induction to be on top. To use the harness and set/up I would keep the engine the way it is. You can modify the look, but you're messing up a good thing if you change the intake design and induction not to mention you will lose performance and need to retune it. It's worth mentioning that yes LS7s have a history of dropping valves. If you mod it and it drops a valve, GM will unlikely cover it,

 

Good project my suggestion is instead of modifying the engine to fit the hood modify the hood to complement the new engine.

Is a plug and go play, easier to impress people with an ls7 that actually looks like one that one that needs explaining IMO.

I'll take the intake mods money and get a killer set of aftermarket heads change the cam dress it for party.

 

The warranty is the big issue to me right now as well. I'm not sure how long it is or when it actually starts. I saw on line that it's one year, but was thinking it was two years. We ordered the engine in December. It was delivered to the frame builder in January. We'll pick up his finished product this week, but the rest of the car won't be complete by the end of the year. So, when does the warranty start? If it was last January, it may be out of warranty before I drive it the first time. As to performance, I plan to consult with professional engine builders for advice. Certainly I don't plan to spend a lot of money just to lose performance. However, changing heads, intake, and throttle body COULD result in significant power GAINS, if done correctly by people who know what they're doing. I agree that if the warranty is two years and it starts when the car is complete, this is a looser idea.

 

I'm not really looking to add power, so I won't be going that deep into the engine. The L88 air cleaner idea may be too much. We're doing throwback valve covers of some type for sure. That may be as cool as I can get it and make any sense of what I've spent.

 

What were your power goals? Probably could have had someone like Texas Speed, mast motor sports, urban etc build you an engine. Again cost and reliability and money is no object. A new LS7 and tearing into it is big money.

 

I'd be fine to just maintain what it has already. All I really want is to address the valve issue, change the valve covers, and move the air cleaner. It didn't seem like such a bid deal. Maybe it is.

 

Shouldn't be too much to check them. Maybe $500 or so to replace guides and a valve job. Pulling the heads will definitely void the warranty tho.

 

I guess getting them to pull the heads is out of the question. They'd have to admit they have a problem to do that, and that ain't happening. I'll try to find out about the warranty issue today. If it starts nearly a year from now when they finally hand me the keys and it lasts for 2 years after that, then this is a no brainer: skip any mods that'll void that warranty.

 

Swapping intake will void the warranty, and they typically are 1 year from purchase date.

They have no clue when you fire the motor up, only the day your invoice shows.

 

Well then, I need to determine "invoice date". If it's January (which I think it is) then I'll never have ANY useful warranty on this engine and can thus do whatever I want, starting now. There no way I can foresee this car being on the road by January. I'll bet one never dropped a valve, sitting in a frame while a car is being built around it. It'll be out of warranty with zero miles on it.

 

Call GMPP. Would really be surprised that they would sell new LS7 with valves and guides that were identified long ago as problems.

 

I figure they'll say something along the lines of "absolutely fixed, no problems". I'm not sure that'll fill me with confidence.

 

Call the techs at Scoggin Dickey at 1800 768-4108 and ask them what different valves/guides they put in their LS7 crate motor SKU 19329246 ($13,600.00) then were in the original LS7. If you don't like the answer, don't buy.

 

Can you explain that a little further? Are you saying that the LS7 valve issue has been fixed? If so, I'm all for that. I replaced an engine in my truck last summer. There's no way I want to tear into another engine if the issues have been addressed.

 

Fixed? I doubt it. There have been reports of Z28s dropping valves. Some searches will say it's the exhaust valve that is suspect. It's simply a gamble imho and a warranty has you covered. Without a warranty I wouldn't not want to pay new price as it gives room to rework the heads. For $14K however I would have an engine built.