1987 305 TBI Swap Candidates

[jaxwithanx]

Hello, my grandfather's '87 305 TBI just quit on him finally and he was looking to swap in a larger displacement engine. At first after some research we were pretty sold with sourcing a 6.0L complete swap but after some more thought we have decided to just go with a less involved swap right now. Basically, my grandfather wants to keep his computer and wiring and swap in a 350. Can his current heads, intake, wiring and various gear stay and just bolt right up and on to a 350? Eventually he wants to look at other intake options and electronics but right now that is not the concern.

We live in Houston, so finding a good shop for a crate 350 or rebuild shouldn't be hard (any shop or local suggestions welcome) but I just wanted to get a read on what we "need" to be swapped out to accommodate a 350.

Thanks for any input!

[fanmanj]

Find a 96-99 vortec 350 longblock, everything swaps over to it from the old 305, except for the intake. I think there are several companies that have the intake manifolds to put the TBI setup on the vortec heads. With that combo and some headers you should be putting about 275 hp at the crank.
BTW, if you change the cam in the vortec, keep it very conservative. Vortec heads require mods to have anything over .450 lift, and TBI doesn't like large cams, as it runs off of a MAP sensor, and it can't meter fuel with the vacuum jumping all over.
BTW, don't bother with the TBI 305 heads, they are a swirl port design with small valves... I.E. They suck. Vortecs are the way to go.
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[jaxwithanx]

Originally Posted by fanmanj

Find a 96-99 vortec 350 longblock, everything swaps over to it from the old 305, except for the intake. I think there are several companies that have the intake manifolds to put the TBI setup on the vortec heads. With that combo and some headers you should be putting about 275 hp at the crank.
BTW, if you change the cam in the vortec, keep it very conservative. Vortec heads require mods to have anything over .450 lift, and TBI doesn't like large cams, as it runs off of a MAP sensor, and it can't meter fuel with the vacuum jumping all over.
BTW, don't bother with the TBI 305 heads, they are a swirl port design with small valves... I.E. They suck. Vortecs are the way to go.
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But I can keep the same accessories, computer and wiring? If all I need is the Vortec longblock and a new intake that will probably be the route I go. I figured I would at least need the ECU or a chip/flash (I'm not very knowledgeable when it comes to computer controller portion of engines). Any suggestions or ideas on the intake I would need to mate it with the TBI?

Originally Posted by Warrens69GMC

350 crate motor-

http://sdparts.com/details/gm-goodwr...gines/12568758

then you need the 350 chip (Tbi chips), knock sensor and injectors (auto parts store)

I originally thought about getting gen specific crated engine myself but I knew I wanted to incorporate as much of the latest tech as possible (within reason) - like the Vortec heads. And for less money I imagine I could find a well rebuilt Vortec engine...

[Warrens69GMC]

350 crate motor-

http://sdparts.com/details/gm-goodwr...gines/12568758

then you need the 350 chip (Tbi chips), knock sensor and injectors (auto parts store)

[jaxwithanx]

Fanman, I assume you were talking about something like this?

http://www.jegs.com/i/GM-Performance...oductId=750534

Hopefully I can find a used one. I don't need to worry about keeping the EGR and smog legal. Seems a little counter-productive to mate such an old intake on newer generation heads and block but I guess that's what it takes to keep the ECU and wiring simple, am I correct?

[fanmanj]

That's the intake. I would Swap all the egr stuff from the 305. It'll keep the check engine light off. Not to mention, you might get spark knock without it.
All your accessories will bolt up. You might just wanna go to the local junkyard and grab a PROM chip from a 350 TBI computer to get the most power. Or if its in the budget, have a custom PROM burned for the truck. I'm 99% sure the injectors are the same, so no worries there. By far I think the vortec swap is the most bang for the buck.
Those intakes pop up on eBay from time to time, so check there for a used one.
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[cue1go]

Why don't you just put a 305 back in it and be done. Especially if you are going to address a 6.0 later. Precision Motors is a good resource for motors in Houston. Competitive prices and I've never had a problem with the 4 long blocks I've purchased from them. 2.5, 3.8. 305 and 350.

[jaxwithanx]

Well, ended up going a slightly different route, to put it mildly. I'm having a 383 built locally with Vortec heads setup for TBI for about the same price as I would have spent on buying the 96-99 Vortec crate (not including the Vortec to TBI manifold). Ready to drop in, except I will need a larger TB unit and chip. I've got a Holley 502-6 throttle body (670cfm) with less than 500 miles on it that I'm pretty sure will do the trick, any ideas on that?

Also, while I'm at it I plan on going to a true dual exhaust setup before I get my chip programmed. Any suggestions on headers (diameters and brand), mufflers or having a crossover pipe or 'X' setup? The engine will be rated for around 375 HP and 425TQ but I don't plan on running it WOT down the road and track often. Would like to keep more low-end, street usable power than completely free flowing system that is better suited for dragstrip.

[Warrens69GMC]

You will need to run a adjustable fuel pressure regulator and you WILL need to raise the fuel pressure, from the 12psi to around 21-24psi. Depending on the rating on the fuel injectors, you may need to replace them.

You might want to invest in a "flashable" computer rather than relying on someone else doing the tuning from mail order (ordering chips from internet)

http://www.dynamicefi.com/

[jaxwithanx]

Yeah I figured on raising the fuel pressure. I'm just hoping the pump will be able to keep up. I also need to find a spacer.

[Jonboy]

Use a fuel pump originally from a 85-89 Corvette. It will have the flow you need, and will bolt right up. The regulator will return what it can't use.

[jaxwithanx]

Originally Posted by Jonboy

Use a fuel pump originally from a 85-89 Corvette. It will have the flow you need, and will bolt right up. The regulator will return what it can't use.

So keep the stock in-tank and run this pump in-line on the rail?