Alright, I'm in the research stage of swapping my stock 305 TPI motor to a 350. I need to get this engine replaced before I send it in for body work. I don't want any shop people crawling all over a new paintjob, lol. To give some background...

My original 91 TA had a 305 which I swapped out for a brand new GM ZZ1 crate motor, back when they first made those. To the best of my knowledge, it was a straight swap/bolt in. The new motor took my original TPI intake/setup, AC, PS, everything. So, essentially, short of looking shiny new and having black valve covers, it looked factory.

At the same time, they bypassed the stock computer with the worthless piece of crap system known as the Accel DFI computer, with the stock computer running the tranny, so I was told at least. Mind you, this was the DFI computer from 1993/1994. Anyway, long story short. The Accel computer fried itself while cruising down the road about a month after install, Accel refused any responsibility as did the shop I had the work done at.

Today, I have another 91 TA with a 305 I want to replace with a 350. Essentially, I'm looking for a similar setup. Direct bolt in to my existing TPI setup(which will be ported, polished, etc, either during or after the engine is in). The new engine has to take all the existing components. AC, PS, TPI, etc.
I have little knowledge of full engine assemblies. So, what would people recommend based on my outline? I'm not looking for someones used motor, but remanufactured or new. HP is up in the air. This isn't a full time track car and I won't be racing every single car that revs its motor at me. At the same time, I'm looking for HP in the 300's somewhere and torque, well, I never truely understood that, so...

The car has a brand new full 3 inch Flowmaster catback, with a new 3 inch inlet/outlet converter installed and that's about it. I was looking at the ZZ4 motors, but those seem to need some replacement of heads or whatever to get it to work with the TPI and something about the EGR setup. Maybe its the same thing, I dunno. I'm not really looking to piece a motor together, so I don't want to go a bare block route. I'm looking for something along the lines of, if not the ZZ4 motor which has eveything already bolted up(short of the TPI setup/intake which I'd be swapping in anyway.)

Also, most definately, the stock manifold and Y pipe will be replaced with shorties and a new Y pipe during the swap. So no worries about me chocking the motor on that end. I've done searches and most people just want to toss in an LS1 or something else that isn't keeping my TPI setup, so I decided to make a new post with my specific needs. Also, just so I don't have to answer it later, the TPI setup isn't negotiable. I've always liked it and I'm keeping it. Modified as much as can be, but still keeping that stock TPI look.

Also, what outside of the engine will need modification? The stock computer, can that be used with a new programmed chip or will I need a new computer entirely( please don't suggest anything Accel ) Anything else?

So, does anyone have any suggestions on which motor to use? and from where to get it.

 

There are some half-truths in your information, let's see if we can sort through them.

ZZ4 isn't a "direct" bolt-in with a '91 TPI, but it isn't that far off. The EGR thing isn't that big of a deal, since the '86-1/2 & up Vette TPI used the same heads as the ZZ4 does, the exhaust can be externally plumbed up to a Vette base. Other than that, your SD PROM will want to know what it's running, so do the PROM tuning/change thing. I've heard that one accessory bolt hole needs to be drilled & tapped on the front of the Al head, not a biggie unless you find that too intimidating.

Another decent choice is the SDPC Vortec TPI crate http://www.sdparts.com/product/SD360...ripEngine.aspx . They say stock PROM, but that probably means MAF, which you don't have. I'd still recommend PROM updates.

Either engine should have aftermarket runners, and larger TB would also be a good idea. Along with 22 lb injectors.

I realize neither of these is a bolt-in, but the old saying that's been around for at least 3 decades still applies - "There ain't no such thing as a 'bolt-in'."

 

The Vortec engine you linked looks to be exactly what I'm looking for. Not only that, but they list a kit they sell for the EGR issue. They've replaced the intake base with a TPI base, which I would have needed to do anyway so that's a plus. I'm guessing I should be able to swap over the items not included such as the water pump, etc.

What about the distributor? I won't be using my old one, that's for sure. Will another stock one from my year work? Not sure if its there's a difference between the 305/350 models but I'd assume no, at least stock wise.

Prom updates would be a must anyway. I'd highly doubt a 305 stock prom would provide exactly what the engine requires.

I'm guessing the new 19# SVO injectors installed on my 305 will be useless so I'll need some 22# ones like you said.

I will say though, after looking this over it's pretty much a drop in job. A couple odds and ends will need to be changed, but really it won't require hacking everything together to get it to work, plus that new intake base will be very nice.

Let's see... I'm guessing new engine mounts, replacing the new stock ones I had installed, or will those be fine? They're about a year old. Tranny was installed the same time, so that'll handle it. Maybe a new flywheel? Not sure the new engine comes with one. The rear end I'll deal with later on and most of the steering and suspension has been replaced. Yup, this is looking very good. Thanks very much for poiting out that Vortec crate motor. It seems to be exactly what I need.

 

Everything external to 305 vs. 350 is identical. Distributor, mounts, accessories, flexplate.

22 lb injectors would be the best bet. You might be able to get by with 19 lb and upping the fuel pressure, but that's not good for the injectors and is more of a bandaid approach.

If you do go with that engine, let us know how it turns out.

 

Ive also been staring down the Scoggin Dickey crate for a while now. Heres a good for you though, If i was to flag the egr instead of going witht he egr kit will that work. Would also go with the Edelbrock runners as it says that it used for the dyno pull. Basicly what i would like to do is take the crate, use the edelbrock runners use the 22# injectors flag the egr use the stock distributor but use the msd cap and rotor as well as wires. leave the TB alone (unless i need to change it to 52") flag the AIR and use the slp headers w/o air (of course) smog pump will be deleted so ill also pick up the pully for it. Rumors have been going around about the valve spings on the heads of just smashing into peices, wondering if they fixed this propblem. I already have a T56 on its way to replace my 700r4 and ill be using 3.70 rear gears in my 9 bolt rear, all and all basicly flag egr flag air get rid of smog pump slp headers stock injectors and possible a 52"tb. would this work if i just flag those two items????? any other info that could hand out please let me know. Also the car is a 1989 Chevy Camaro Iroc-Z L98 with all the goodies cept 1LE N10 and G92. thanks

 

how do you know if you have a G92 option in your car, to my understanding (mines an 88 iroc) if u have the 5.7 in 88, u probably have the 3.73 gears???

 

Look in your center console. There will be a data sheet pasted on the side, inside the console. it will have a bunch of number and letter codes. That is your RPO code sheet, look to the point of the start of the G section and you'll see if you have a G92. Best way for me to let ya know.