85 305 TPI to 350 TPI

Anyone know what parts I would all need to do this swap? I will be re-using my TPI manifold and plenum, headers, flywheel, and all the accessories (alt, starter, etc..) I'm not going to re-use the damper though because I believe it would be smarter to replace it. What I am wondering about is more along the lines of electronics. I already know I need bigger injectors. Speaking of which... does anyone know of any injectors that I could use for the 350? They need to be 24lb or higher and decently priced.. all I can seem to find is Accel injectors, which I would not buy unless it was a last resort. Are there any sensors I need to change when I drop the 350 in? Also, is there a temperature sending unit for the dash gauge that fits in with headers? Thanks!

morley...

*bump* :smile:

305 and 350 are pretty much identical. Everything you had externally on your 305 should interchange to the 350 and also on a side note. I have some 24.9lb injectors from a LT1 corvette which had 39K that are interchangable with TPI's if interested but to be honest, unless your doing some modifaction a 19 or 22 lb injector will serve you just fine. 24lb injectors are really meant for 300 - 350 horse engines.

Also the temp sensor in the head should not interfere with the headers unless your working with some fabricated headers.

Also, your right. Accel injectors should not be a first choice. They are well known for leaking right out of the box.

Yeah, I am not too much of a fan of their injectors. I am planning on doing quite a bit to the motor before I put it in and also planning on 150-200 shot of Nitrous Oxide. Looking to get about 300-320 HP with the N/A engine though also. What do you need for the injectors? Also, do you happen to know the part number for the temp sending unit? Thanks!

You will need to change; Knock sensor (get one for a 350), injectors (need 22# but stay away from the Multec's), calpack for a 350.

I can't seem to find the parts number on www.gmpartsdirect.com (http://www.gmpartsdirect.com) to the coolant temp sensor located in the head but a simple call to your local dealer will most certainly get you that number,. As for your comment on what I need. Do you mean what do you need to make them work with your ecm or what do I want for them?

I mean what do you want for them money wise :smile: BTW thanks for the info Morley. I will probably have to custom tune the PROM though.

Shoot me a offer threw PM and I will respond with some pics of the injectors and if I accept the offer. I don't really like offering goods in open forum since I don't allow members to make threads of classified items . I also think I have a knock sensor for a 350 but have to verify its part number if interested. I can also get you a pic of that.

John

I can't seem to find the parts number on www.gmpartsdirect.com (http://www.gmpartsdirect.com) to the coolant temp sensor located in the head

Because there isn't one on a '85. Only the gauge sending unit between cyls 1 & 3. The actual temp sensor is on the front of the intake manifold.

lol , ah that would explain it. Thanks

No prob, drove me nuts too, and I own one. :banghead:

wrightz28:
Do you happen to know the part # on that sending unit? Thanks.

SU109 for the wells through autozone. This same was used on alot of Gm's of the day, even my 87 Buick 3.8 uses the same one.

i put it in both cars, the Buick is fine, however I'm still having irregular fan op in the Z28, which oculd be the hack job on the wiring. But you may want to check out Chevy or TPI PARTS (link avail on TGO). I only say that becaseu the 85 ECM seems very twitchy to some generic stuff.

Unless you are going with an engine that is wildly different from the stock 350's or going with injectors larger than 22#, you should be just fine with a factory calpack...unless you have an 85..then you don't have a calpack, just a bare PROM and it gets to be more fun. I swapped my 85 from the stock 870 ECM over to the 165 ECM. The 165 is easier o tune and more widely supported..not to mention that the $800 MAS module was replaced by 2 $15 relays.

So Morley, you basically made your '85 a 86-89 sytem then?

So Morley, you basically made your '85 a 86-89 sytem then?
Yep. Didn't remove the harness though, just repinned and spliced it. The instructions are here http://www.eecis.udel.edu/~davis/z28/ecm_swap/
Took 3 hours to do it, including tripple checking all of the repins and wire splices. One bit of advice....don't go his route of getting the harness for the relays and mounting them in th stock location in the engine compartment (he boreda hole in his fire wll to run the wires). I just got the relay sockets from Pepboys with 10" pigtails on them, wired them in per the instructions and then mounted them on the bracket that the MAS module was on and mounted that to the new ECM, just like it was on the old ECM. Nice, neat, tidy install.

Sweet, I'll check that out. I hate the way this engine mgmt. sytem is setup, especially this piggyback garbage.

***followup***

errm, I'm going to have to find the "ECM repinning for dummies" version. I get the overall gist of it and what's required, just the overall how to, "pin AB to E.T." stuff gets me lost.

wrightz28:
Thanks, but actually I was curious about the part number for the gauge sending unit for the dash, been looking for one for a long time still cannot find one.


Morley:
I was actually going to include the 165 in my *planned upgrades* for this year. I had already read that tutorial and thought it to be quite interesting. It is going to be a pain to tune the PROM though because of the odd mixture of crap I will be throwing into the motor. Do you have any experience with N2O? I am curious if I need to do anything with the fuel system? I am probably insane for wanting to stick with fuel injection considering I could whip a carb on and be done with it, but I like a challenge. It seems that you are the one to talk to about doing the swap though. Any idea how much HP and TQ will the 700R4 and the stock drive shaft/rear end take?

Thanks to all of you for replying :)