ehmcj

Hi guys, newbie first post - NICE SITE!

Read through the 305 to 350 swap and TBI guides tons of great info! But I still have a couple of questions

ESC - there seems to be some confusion if it is required to change it when swaping from a 305 to a 350? Any consensus? Also does it matter if a roller cam motor is coming out and a non-roller is going in?

I have a 91 caprice with the LO3 and am putting in an older 350 (with a mild TBI safe camshaft from Comp 12-238-2) and do not want to mess around with custom programming. My ECU is a 16136965 code AXCX, I can order a 350 chip from GM or just pull the chip out of a 350 caprice in a junkyard?

I have found the 350 knock sensor and 350 TBI injectors with no problem, running into issues with aquiring the ESC and chip

Thanks for the help!

RFmaster

ehmcj

Welcome to TGO

ESC there is no real confusion about ESC modules. Let me clarify myself - find the one that works for your 350. From what I was to determine early ESC modules were tuned differently and produced slightly less false knock detection.
In my case, I found that GM# 16128261 ESC module and GM# 10456288 Knock Sensor (KS) work OK on my non roller 350. I still get some false knocking, but I am not sure what the real cause of the noise that is being detected by KS. My advise is to get a few different modules from JY and see which one works best.
I have '6965 ECM which I pulled from 5.7L Road Master. I'll take a look at it tonight and post BC code. GM will charge you more than twice of the ECM cost from JY.

Regarding your cam selection 12-238-2. It is a nice mild cam for a Carb application, but it may not be ideal for near stock TBI 350. The big problem with this cam is its Lobe Separation (LSA) 110 deg. This cam will produce a nice loppy idle with about 11 to 15 inches of vacuum at idle (650 to 700 RPM). Since you are sticking with stock 350 EPROM this will cause ECM to hunt at idle and run rich (VE tables being off for a given MAP values). For near stock application (i.e. no EPROM tuning) I would recommend
to find a similar cam , but with LSA greater than 114 degrees. Wider LSA will result in higher vacuum values which a closer to stock (IIRC stock runs about 18 inch-Hg). Just be forewarned that once you go to after market cam eventually you'll have to look into EPROM tuning to extract maximum performance from your ride.

Good Luck

//RF

ehmcj

wow, RF thanks for the fast reply!

Reguarding the cam choice, i got to learn to read my own handwriting! The cam is really 12-388-4 which is supposed to work with TBI w/o performance chip. still only has 112 lobe sep though..... Strangely the only "Computer Controlled" camshafts they have with more than 112 degress, comp says require tuning. I would love to find the specs for the 9c1 LO5 cam so that i could duplicate it in a non-roller application

I went to GM abount an eprom and they have an L05 eprom (16220839) thats about $67 (CDN) thats set up for the 350 and they gave me the phone number for a company that bought up all their 9C1 eproms (16165380) and they are $90 plus shipping (which is always like 40 bucks to Canada, stupid border). I am trying to duplicate the power of the 93 caprice 9C1 (about 205hp and 300 ft lbs of torque). I know that I will need the 65lbs/hr injectors with the 9c1 chip vs the 61lbs/hr with the LO5 chip.

I really just want this car to be dead reliable, but I can't stomach the thought of putting a 305 back in it. I got a smoking good deal on a GM crate engine 10067353 (which is identical to the 290HP 12499529 except for the camshaft, which I'd have to change anyway).

I know that i can modify the intake to work on the older style heads and other than a new flexplate the engine will bolt right in! I've got a handle on the injectors, and knock sensor (ESC now too) and once I chose a chip, hopefully this will be an EASY swap!

Thanks!
Andy

RFmaster

Well I have similar problem LOL.

Regarding 9C1 camshaft used with optional LO5 for '91 - it is nothing special since that engine was only rated 195HP@4400 & 295ft-lb@2400RPM. For 92-93 9C1 LO5 special camshaft and valve train components were available and engine output was raised to 205HP@4200 and 300ft-lb@2400 RPM. These cars came equipped with 3:42 gears to get these behemoths moving quickly of line.


IMHO I would not spend $90 for 9C1 EPROM. It is simply not worth it since any after market camshaft will end up in a completely different engine characteristic's. Instead, read a sticky how to tune and burn your own EPROMs - see above. All the tools are readily available and stock PROM images can be easily downloaded as a starting point. The only issue is that '6965 is not widely supported, but both TunerPro and TunerCat have definition files for it.

CCA-12-388-4 camshaft is a mild grind (252/260) - it is probably close enough to original 9C1 cam used in 91. Before I go any further I should tell you that I am no expert in 9C1 and LT1 engines. Check www.9C1.com for more information, and other sources.

Before you commit - I suggest that you read these stickies very carefully and ask questions if you are not sure.

//RF

kdrolt

Go to a junkyard and get either the chip, or chip+ECU box, from an LO5 Caprice copcar 1991-1993. Get the ESC and the knock sensors too, since they'll certainly be correct for use with a 350. This will be much cheaper than buying new; and you can always buy new if you fail to find what you need at the JY.

The LO3 TBI will work but you'll either need larger injectors (to feed the 350) or run slightly higher fuel pressure. Getting a Walker aftermarket larger 9C1 Ypipe would help the exhaust too. See this thread for more 91-93 TBI Bcar info:

http://www.impalassforum.com/vBullet...d.php?t=173358