I need to know which numbers on the TBI are the part numbers. I have a recently purchased 91 RS. Was a 305 TBI but the PO blew the engine so an uncle that "knows about cars" dropped in a 350 from a 94? truck. This thing will surge and miss badly at times from a stop and usually surge/misses at about 45 mph. I am wondering is they maybe did not install the knock sensors in this replacement engine...
Several thing make me think they just installed the 305 ignition and TBI on the 350. The number on the top stamped in on the pass. front of the TB is 86290Y, there is a sticker with a bar code and the number 1039 there too. This is on the flat surface outside the ring around the injectors.
On the vertical surface on the edge are the numbers 17091039 and 7830 KDK.
I bought this for my son and is a father son project. The engine in this thing has the fuel pump boss on the right front but there is no block off plate and the ground has been bolted to one of those threaded holes.
We are trying to decide if we want to try and keep the TBI or go ahead and do a basic 5.3 ls swap. If we can save the TBI great... but the LS would be fun. I figure the tbi and computer and harness might be of some value to someone and can offset some of the cost of the newer LS. Comments and help are appreciated.

John

 

Ok, a couple of things here. 1) make sure the injectors are 350 injectors not 305 injectors (look at the colors on top of the injectors and report back or look them up using search function.) 2) some people will swear that the 305 prom will work with no problems, but the cylinder volume values are different, and if it has 350 injectors, the BPW is incorrect which can cause problems. Also not sure if you have a laptop, but get an ALDL cable and free software and datalog the car, that will tell everybody where to look to find your problem.

 

If a 350 was dropped in, like mentioned, it needs a 350 prom (from a 350 TBI car like a Caprice or truck), a 350 knock sensor, and 350 injectors in the TBI unit, and it should run fine if all else is good.

 

OK jim, I looked at them and they are just gold looking. Is it a paint? This thing is flat dirty. I started it up and it looked to me that the passenger side injector was flowing a lot of gas on the back of the butterfly at idle. Maybe this is normal? I dunno.. I have laptops... yes several. ALDL is that a parts store part? Where do I stick it.. (Yes leaving that one open.) Any preferred software? I will do that maybe Monday, I have survival camp out with the Boy Scouts and then Daytona 500 Sunday.

I was wondering if since it is supposed to be a truck engine and probably doesn't have a roller cam would that confuse the knock sensors? Are the knock sensors located in the sides of the block? Again newbie questions. I know very little 'history' about the car because the PO was a high school kid who jus thought it was cool to burn the right rear tire off it.

Oh and it does what some threads are saying is the EGR too. It does not have that rich running smell ever so I am pretty sure it isnt running overly rich all the time. Again thank you all.

 

The ALDL cable is the cable that plugs into your OBD1 connector (ALDL) and your laptop. It is available at moates.net or you can build one if you are handy with electronics. The software is tunerproRT and it is a free download you can get off moates.net. If they swapped the entire engine, Throttle body and all, then you need to put a 350 prom into your computer to get it to run better. That's really not very difficult if you have pick and pull junkyards around. Find your ECM, and look and see which ECM it is, then go to the JY and find the same ECM out of a 350 car, open it up and pull the prom out (or memcal depending on which ECM you have) Just replace the prom in your ECM, no need to buy a new ECM.

 

OK. I know it has been a while but I have been busy building a shop to tear this car apart without getting busted by the 'man!' I finally figured out what was ment by the 'colors on the injectors'. Mine are Green and White. I found something somewhere that says these are the 305 injectors, which is what I assumed. They just stabbed the new engine under the electronics from the 305. So I need the new injectors... 55# or should it be 62# injectors? This is not going to be a high performance rebuild, just simple with an eye to mileage and fun.
If I can find a 350 Caprice I need the TB and the computer? What years? I have heard different things. Also can I use the trucks TB/computer? Thanks.
I am looking for a late 90's vortec type engine that already has the roller cam setup in it. I know I will need the vortec intake, and knock sensor... Just want to get the right parts the first time..... Thanks everyone.

 

You can still use your existing ECM, but you'll have to invest into EPROM burner and get friendly with TunerPro. Check out stickies on this subject first.

The 55 lb-Hr injectors (green -white) provide just enough fuel at stock fuel pressure for a warmed over 305, least for 350!! All SBC TB's (220's) have the same bore size - 47mm. You can use 4.3L TB on 350 if you swap in larger injectors. You'll have to source 350 injectors and bump fuel pressure from stock 9 to 13 PSI to about 15 to 18 PSI. This can be done very easily with a stiffer fuel pressure regulator spring. Increase in fuel pressure improves atomization of the fuel spray - but fuel related constants and VE, AE tables (in the EPROM) will have be altered and adjusted to suit your engine needs. Higher fuel pressure will also support higher HP to a point. This requires data logging - once done you can definitely feel the performance difference.

Roller cam is a plus - but make sure to pick the right one to match your engine - drive train combo.

Take the time to figure out where you want to go, set goals and plan ahead.

//RF

 

EH?

Stock SBC TBI bore is 43mm.

 

You don't need a different TBI unit - the TBI units are the same - just put the 350 injectors into it.

You don't need the entire ECM, just the prom chip - from a 350TBI Caprice or truck.

And don't forget the 350TBI knock sensor - goes in pass side BLOCK (not head).

 

Too quick on keyboard - stock RPD TBI 220 bores are 1-11/16 (43 mm).

You can only swap EPROM chips between ECMs with the same service number - for example 1227747 to 1227747. You can not swap EPROM from 1228746 (350 Caprice) into 1227747 (truck).

//RF