I am planning on putting the 350 (.030 over) that I have in my garage into my LO3 Formula. It came from an '86 GMC Suburban. It has been fully rebuilt by a machine shop who did the cylinder work, and dipped it and the works.

For the install, I think I am going to just put in a new cam, intake, and a set of headers. With the project I look to achieve around 350 hp as a rough estimate. (This is down the road; after heads, roller rockers, fuel injection, etc.) For now I would just like to put the correct internals in the motor for down the road.

What are your suggestions for Intake/Cam/Headers? I dont really know too much about cams and their specs. I want a little bit of a rumble from the cam, but its a mostly street car, with occasional races at the track for fun.

Any suggestions welcomed. This motor is not a roller.

 

Edelbrock RPM Airgap, XE268. Headers? Whatever you want!

 

Are you positive that these will work on my motor? It was previously Carburated. Also the block is from 86 so it is not a roller assembly. I think they called it "flat tappet"? The word "hydraulic" comes to mind, but I can't remember whether it was or wasn't.

Is that Comp. Cams' XE268, or what brand?

Also why would you say these items? Is there any particular reason that you chose them? Please elaborate.

Thanks

 

The block is basically the same whether from a truck or car, carb or fuel injection.

The heads are a different story. Most likely the stock truck heads are small valve, small port things that won't support many other horsepower mods. They may not even accomodate the lift of the cam recommended (which is a Comp, by the way).

Cams - "hydraulic" is the only thing the factory has used since the early 70's. They've gone from flat tappet to roller in most applications, trucks receiving them later than cars. Your LO3 is roller tappet/follower hydraulic; the truck was flat tappet hydraulic, as is the suggested Comp cam.

Were you planning on keeping the TBI, or going carb? That will make a difference in all the other choices you make (except headers, perhaps).

 

Thanks, 5.7 that really helped.

I plan on keeping the TBI, with bigger injectors for now. Eventually a better Fuel injection system down the road.

Would Edelbrock TES's work on both my LO3 now, and this 350? They should, right? Since they are the same block?

So you are saying that the XE268 will work, but I might need new heads at this time too? Would a set of L98 Alluminum Heads work? Or would I have to go with something specific to my '86?

I appreciate all the help.

KZad

 

The XE268 has .480" lift (if I'm reading the info correctly), which is marginal on stock heads. You'd certainly need upgrade aftermarket valve springs, and probably retainers.

The headers will work. TPI application has the better parts, though, and Hooker is generally considered better (at least the y-pipe) than the TES.

I prefer doing all of this kind of work at the same time - much easier to replace a cam or heads when the engine is out of the car than when in, or doing the work twice. Same for headers.

The aluminum Vette heads are pretty good. Worked over L98 heads are good, too, and your TBI manifold would bolt directly to them, while bolt hole mods would be required with the Vette or '86-earlier style heads. If you get an aftermarket intake like the RPM, it's made for '86-earlier heads. Again, the block isn't what's dictating your parts needs (except for cam), it's what you bolt onto it.

I hope you realize these changes will require TBI mods. That forum would be the better place for info on that.

 

Yup we can help you out over there. You need to make sure you select a cam that is TBI and PROM friendly. There are many things to upgrade before you change displacement.

 

Shifty -

What cam would you suggest that would be TBI, and PROM friendly? Would the suggested XE268 be a good choice? I also have a friend who can scan and burn chips for my car, so I think I am okay on that end. I would probably upgrade to larger injectors to compensate for the motor. Would there be anything else? I already have the ultimate TBI mods done as well.

If you think these questions are better served on the TBI Forum, then please move to the appropriate area.

Thanks,

KZad

 

I do not know the specs off hand of that cam but came size will be limited by TBI friendlyness and head selection. I assume you will have a full exhuast, larger than stock TBI unit, intake and gob and gobs of tuning. Tuning will be the biggest factor in making your combo run good. Feel free to post a more TBI specific question if you have one. I would recomend that you read the sticky at the top of the TBI board and you will see what it takes to make a modded TBI system.