i spun a rod bearing in the 305tpi in my 1992 trans am and i was given a 350 but i wanted to know if i put my stock 305 heads and tpi set up on the 350 will it run right? I know it wouldn't run at its full performance but would it run like a normal motor, i just want to be able to get on it every now and than to have some fun and drive it to work and school until i have the money to buy new heads and a new eprom. i will put a 350 knock sensor in it but i don't have the money to put all the other stuff in it at the moment. will it run right though?

 

It will run but probably not well , i would say if you just need to keep it running until you can go through it correctly you can do it but the small chamber heads will raise the compression slightly so watch out for detonation and the small valves wont help either ...

 

exactly like you said i need to run it until i can go through it correctly but people are saying you have to change this module and that module, what would happen if i ran all of the stock 305 stuff on the 350? knock sensor all the stock modules i just want to unplug the 305, pull the top end off bolt it to the 350 drop the 350 in and plug it all back in and just drive like that untile i have the money for the proper parts because right now i'm driving it with a rod knock and it scares me not knowing when it's going to go on me. and would it run well enough to beat on some rice? or would it just run like straight crap? I guess what i'm realling looking to find out it what do i ABSOLUTELY HAVE to change if anything?

 

OK I have helped change over a couple just like you are trying to and they will run by just putting the top end on the 350 shortblock and using all the sensors off the 305 but it may run a bit lean , actually the ones we did ran OK but triggered a SES light with a lean condition not serious enough to do any damage though a plug check showed slightly light coloring but no burning or overheating of the plugs it would allow you to drive the car but thats about it power would be down as would mileage but you can get away with it ..if you can get the thick head gaskets .040 it will help with the compression (keep it down with the 305 chambers smaller size)

 

First off,
Yes... you can use the 305 heads. Yes the compression will change, but not enough where 92-93 octane could not handle.

You can run every bit of your stock 305 stuff on a 350 and have it run fine.
As you know, 305's have 19 lbs injectors 350's have 22lbs. You can have your prom modified to accept 19 lb injectors easily, and have it running the way it needs to.

Yes, the knock sensor is different and is more sensitive if you use a 305 sensor in a 350. However, I am running a 305 knock sensor in a 355 with no problems whatsoever. You will need to change your electronic spark module as that is different.


recap..
Change your knock sensor
Change your ESM
Change your prom for 19lb injectors for a 350

You're done.

You will also pull a couple extra ponies for the higher comp ratio too.

 

how much will an electronic spark module cost me? and where is that located on the motor?

 

brand new $75 or less.... it is located on the firewall by the drivers side. It looks like a huge black square with a connector on it. It is left to the row of three relays.

 

As I understand it the later TPI (speed density) systems used the same knock sensor whether 305 or 350, and the module is built into the ECM.

Put in a 350 PROM and 22 lb injectors, and it should run fine.

 

the prom is the chip right i can order an aftermarket prom can't i?

 

Correct.

 

Apparently the knock sensors are indeed different. 90-92 305 and 90-92 350 have different part numbers and different prices.

www.tpiparts.net

sen-300 $49

sen-301 $45

I hope this helps.

 

I spent a lot of time on gmpartsdirect.com last year trying to find one for my 350 swap, and was surprised that the later 305/350's had the same #'s. Since I wasn't looking for something directly for that application, I didn't pursue it farther. Those who have the later TPI systems have corrected my statements that you need a different KS for a 350 TPI than what the 305 has.

So, free advice, and (certainly when it comes to me), you get what you pay for. . .

 

No sweat... people make mistakes.. After all there is Ford

 

I know this is an old thread, but I haven't been here in awhile and I'm curious;

Several people have told me that 305 heads (mine are '84 H.O.) on a 350 will send the compression ratio through the roof, since the combustion chambers are a lot smaller. Is this true?...

(Edited for Typos)

 

The difference in chamber size is 6cc. If you add 6cc to the TDC volume, either by dished pistons or thicker head gasket, it'll be the same as it was with 350 heads.

BTW, good to see you around. Was wondering how you'd been.

 

alright, i know that everyone and their sister has asked this Q but, my 86 camaro has a 305 with the quadrajet on top of it, and i am wanting to put the 350 from my truck in there. everyone is talking about injectors and sensors that have to be replaced... but what all will i need to replace since its carburated? like will the oil pans be different and aswell as the heads and intake. im goin to put and edlebrock carb on the 350 though.

 

Every thing should swap right out, the only thing you may want to watch out for is the 7 bolt heads your truck engine may not have them so using the stock manifolds might not work well..
as long as it's a standard 1/2 ton pick up the pan should work, and a small block is a smallblock no matter what size it is so every thing else would bolt up the same .. as long as you are going to an aftermarket carb you just don't use the connections for the carbs emissions.. you would also want to use an aftermarket distributor (Non electronic controls) or a standard Hei distributor out of an older non electronic control distributor vehicle 75-80 ..
depending on the year of your truck engine it should work with no issues ..

 

the motor is out of an '83 3/4 ton 2 wheel drive with an 8 foot bed. and as far as the manifolds go; u say i should just go with some headers for it or what? and i understand what your saying about the distributor; since the amount of space between the firewall and block. and i cant wait to get rid of all them darn hoses and smog crap with that nice Edlebrock 650cfm, also im thinkin about the Edlebrock performer airgap intake.

 

An 83 should work Ok , the issue with the manifolds is the factory heads on third gen cars have an extra hole on the head because of clearence problems on the back port (7 bolt holes instesd of six) the factory manifolds that fit a camaro / firebird use this extra hole where most other engines dont, so using hedders would eliminate the problem if your heads dont have the extra hole ..
the distributer just needs to be a non computer controled one, an HEI large cap will fit you just dont need the computer stuff with a normal carb set up..
the 83 truck would have the computer dist so you probably would want to go with an older one or an aftermarket like I said ..
but other than those items it should be a straight swap...

 

ok cool. as of right now the truck has the quadrajunk in it right now, wtih the HEI dist. the carb is here in the next month or so, thanks