My situation is this ... I have an 1988 Formula with the 305 TBI and 5spd. Car runs good, but I am starting to think about a motor swap.

I have sitting in my driveway, my brother's old '86 Suburban with a rebuilt (magnafluxed, bored .030 over, etc) 350. My dad and brother 2 summers ago took out the motor, had it redone, and put it back in. Its got a carburator sitting on it now.

My question is ... Would it make more sense to use this motor in my car, or buy a Crate motor? What would I have to do to this 355 to bring it equal to a crate motor? In the long run, which would end up being cheaper? How much work are we talking about? More than last time they did it? Any info appreciatied...

KZad

 

So you're saying that I'd be best off using the 355. What cam do you think i should look into?? LT1 or talk espo into selling me his ZZ4? Anything that would suit me better?

What do the Vortec Heads run? Friend of mine says they can be found for around 500 a pair, shouldnt that be 500 a piece? Seems cheap to me. Could I expect 30-40 HP increase with $500 vortec heads?

I have a set of stock injectors from a '94 Suburban that ran a 350 TBI. Would they work (maybe just for now to save money)? Can I just use my TBI with these injectors?

Headers would definatly happen... and my dad for some reason is pushing for a set of roller rockers. Any suggestions???

Also, if this swap does happen ... will I bolt right in, with no problems? I am guessing I would need to use most of the 'stuff' that came on the 355, like the distributor, etc? Would I need to use anything off of my 305?

1. Vortec Heads
2. Intake
3. LT1 or ZZ4 Cam?
4. Headers and Y-pipe

Would 3.73 gears with a posi unit be overkill for this setup? Would 3.42's be better suited, or should I keep the 3.08 for gas milage, and just put in a posi unit?

Thanks,

Kurt

 

Hey I did the exact thing you are thinking about now. I put on the vortec heads and yes they are 656.00 for a pair including the machine work I had done to them for upgraded spring lift. As far as roller rockers, if its a roller cam then yes make it a full roller motor. However you look at it though its less friction which makes your motor run a little smoother but not tons of hp wise. If you kept the tbi you would have to put in those injectors you were talking about as well as a burnt chip for the computer. I recommend though, that you stay away from TBI unless you just want something to drive everyday with more power than the 305. The tbi was in the middle of carb's and tpi and didn't have the performance objective set in mind. My car gets great gas mileage and is a hell of a lot stronger but I am still not pleased with the results and considering going to carb. I don't know of too many tbi's that could touch into the 12's with my motor and vortec intake unless they had rockets in the tail lights.

 

Wow, muncher - U really pulled this one outta the archives!

Believe it or not, although over a year later I am still in the same situation:

355's on an engine stand in the garage, untouched
still dont know what parts I want to purchase.

If you could, send me a list of the parts that you chose to use. Part numbers too if you can, especially the vortec heads for ~$600. Did you cam your motor up too? What's your car run?

I have been told that the motor (out of an '86 Suburban) is does not have a roller cam. I have a friend who will burn me a chip, and for Simplicity sake - it will remain TBI for now, just with the bigger injectors. Down the road when I get it to run the way I want, then I will consider the change to TPI.

Thanks for the help.

Kurt
kzadworney@njleg.org

 

Shewww your right, I didn't even look at the date, just the topic I was in and if I could answer anyone's questions. To break my motor down for you, its vortec heads with upgraded spring lift meaning, I squeezed a 218/224 roller comp cam in it. It has roller lifters and roller rocker arms as well. The parts number for the heads I don't remember, but if you look on the internet for Scroggin Dickie website, they are a GM Performance dealer located in Texas I believe. The only thing you have to beware of Vortec heads is that their bolt patterns are different and if you plan to use a normal intake on them, you would have to get them machined.

 

Thats when the price considerably goes up. I bought an intake from www.gmpartsdirect.com that cost me 260.00 dollars. Its no bigger than the 305 TBI bore size and thats what hurts 55 more cubic inches of power. Now when you say that for the simplicity sake you are going to stay with TBI, I thought the exact same thing. However, with my motor it should be turning out low 13's at least considering the cam, heads, flat top pistons I forgot to mention, and etc. If you wanted to beef up your car and make it run faster and keep good gas mileage then stick with the TBI. I got 21-23 miles to the gallon on a trip across the state.