Hey y'all,

I've been kicking around possible builds for a few months, and I wanted to see what everyone thinks about the setup that I've come up with. I've been wanting to do an LS swap for quite a while, but recent turn of events have really changed the parts available at my disposal.

My '90 Suburban has a GM Goodwrench 350 w/ approximately 35,000 miles on it. It holds 45 psi of oil pressure all day long, never smokes, never makes any weird noises, and never uses any oil (I go 7500 miles between changes without having to add a drop). It's the factory replacement TBI engine with a 9.3:1 CR on 64cc heads.

12,000 miles ago, I installed a brand new set of GM Performance Vortec Heads, along with Felpro Head Gaskets, ARP Head Bolts, and Comp Cams Magnum Roller Tip Rocker Arms.

I also have all the roller cam gear out of my 305 sitting in the closet, which had 25k miles on it.

Last fall the old burb got T-boned by a kid texting and driving, and I just bought a '86 Suburban with a 454 to replace it. I love driving the 454, and I've decided to keep it. That leaves me with the 350 vortec motor without a home. What do y'all think of building it to the following specs and dropping it in my '88 GTA?

GM Goodwrench 350 (9.3:1 CR)
GMPP Vortec Heads
Comp Cams XR264 Camshaft
Comp Cams 26915 Beehive Valvesprings, locks, and retainers
Comp Cams Magnum 1.6:1 Ratio Roller Tip Rockers
GMPP LS Roller Lifters
JEGS Double Roller Timing Chain
Vortec TPI Base
Accel SuperRam Intake
Hooker Shorty Headers
2.5" into 3" Y-Pip
3" Magnaflow Cat-back

I figure it would put me at just shy of 400FWHP and 420 ft-lbs of torque at the crank. In my 3500lb GTA with a TH700R4 and 3.27:1 rear gears, I figure that would make a pretty good little screamer that still got great gas mileage. Would I be in LS territory yet? Eventually I'd probalby be swapping in my T56 with 3.45:1 gears.

Questions, Comments, Concerns?

-cal30sniper

 

Before you order parts, make sure the block is atleast able to take a factory roller cam set up, you might have to get the cam retainer, hardware, ect. You might have to tap some holes also.
I think you'd need to stroke it to reach your goal, to make high hp you'll have to wind it high, thats not a strong feature of the tpi.

 

I have the dogbones, cam retainer, spider, etc. that came out of my 305. The bosses for the roller cam should be in the block, and they may already be tapped. I might have to tap the holes in the bosses for the spider, but I would think that should be doable without tearing the engine down any further than that. Has anyone ever drilled and tapped the holes without completely disassembling the engine? I was figuring that if a person was real careful, he could get the holes drilled and tapped without getting any debris inside the engine.

I also counted on the high-RPM limit of the TPI. That's why I was leaning towards a SuperRam setup. From what I've read it gives the best of both worlds between the Hi-flo Edelbrock Style TPI's low end grunt and the Miniram's high RPM breathing.

-cal30sniper

 

From what I've been reading, the sr will bolt up to the vortec intake only after you do some work to the mounting bolts (counter sink them), so read up on that.

 

I sure wouldn't put a SR on any car I owned, if I wasn't obligated to by CA smog.

By the time you have that Vortec base and a SR on there, you will have about $1200 tied up in it AT LEAST, and you will have torn out half your hair working through all the SR "bugs" especially since any one of those you come up with is going to be used and no telling how old.

A MUCH better plan would be a Stealth Ram. Only issue you'll ahve to overcome is, the TB sticks kind of upwards in the engine bay, and the front of it hits the hood; there are a couple of potential remedies for that though.

Yes you can D&T the holes easily enough. Cover all the drainback holes and the lifter bores with duct tape or someting; and put grease on the drill bit and the tap, and all around the holes, to catch the chips.

 

I'll second the comment about the SuperRam being a can of worms you don't need to get into.
A buddy of mine roadraces an LT1 originally built by Lingenfelter with the SR, and I've heard far too much about what a pain it is to live with.
He goes through an engine refresh at the least every two years, and was finally convinced by his mechanic/engine builder/friend to ditch the SR and go back with with the stock LT1 manifold. It got to the point where his mechanic refused to work on the car anymore because every time something needed to be done, it was twice the job it should have been. The guy finally flat out told him either get SR out of his head or find another mechanic because he was tired of the dilemma of either taking his money or working for free!

 

Well, bad news on the SuperRam then, but that's the kind of stuff I needed to hear.

I don't think I really want to dive into trying to make a StealthRam clear the hood though. From what I've read, on some cars it's a drop in, and on some cars it requires cutting of the hood bracing or re-machining of the throttle body face to clear the hood.

That really only leaves a couple of options. Cheapest would be an Edelbrock style hi-flow setup, but I think that would significantly choke my power throughout the band. The only other reasonable option that leaves would be the FIRST intake. When it was all said and done, it probably wouldn't be that expensive comparatively to go with the FIRST setup when you consider what the cost of Vortec bases alone are.

I've also read some of the FIRST builds on here, and it seems that they too have more than their fair share of problems, especially with tuning and the throttle body setup. Is there any really good options out there for a Vortec base intake that doesn't require cutting up the car?

-cal30sniper

 

MiniRam