This is the swap I want to do on my '84 T/A. I just wanted to hear from others who have done the same swap, and find out what extra stuff for the engine i'll need, what kind of results to expect, etc.

 

This is the swap I want to do on my '84 T/A. I just wanted to hear from others who have done the same swap, and find out what extra stuff for the engine i'll need, what kind of results to expect, etc.

I did this swap in my 84 mcss about ten years ago. I took out the 305 and put in the 350. I also changed the metering rods and readjusted the MCS per the factory manual. It makes a huge difference. Now you can upgrade to the 87-88 computer and use the zz4 chip and knock module but I never found a need to do this. Read your plugs and do timing based on performance and you will be fine.

HTH

John

 

Then you did that swap before the engine existed.

The 350HO uses Vortec heads, which require a special intake manifold, and do not have the exhaust cross-over for the EGR valve. You can get it to work by getting a Vortec Q-jet EGR manifold and plumbing exhaust up to the intake cross-over passage.

I don't personally know anyone who has done it, but the TBI/TPI versions had to do the same thing. ZZ4 conversions have to do the same for the EGR exhaust feed (no cross-over passage in those heads, either).

 

I have a mildly cammed 350 with headers and such with a bone stock CCC, and it works out alright. I feel i can tune the carb to get better performance, but have yet to figure out what kind of rods and hangars to order, and Im thinking of filing down the AV tab to get more air in the motor. I havent revved the motor up lately, but I was thinking my valve springs were worn, just re did the ignition, seems to have helped a great deal. I dont know, i think its time for some more test and tune. But that CCC seems to work all right, and I still get decent mileage.

 

Then you did that swap before the engine existed.

Sorry about that. I forgot about the head change . I had the old 300hp/350 HO.

John

 

So, EGR aside, I should be ok?
My main concern was whether the computer would stay happy or not.

 

Again, I don't know anyone who has done this exact swap. But, the computer doesn't like agressive cams, and that cam is fairly mild, so that part should be okay. It will also want something to send the EGR signal to, so as long as the solenoid is there, it should be happy. There isn't any feedback signal or functional monitoring of the EGR by the ECM.

 

A friend of mine on this board. FIRBIRD has the 350 HO motor with a carb. I will get him to respond to this and tell you some details.

 

I did this swap, I first went with tbi with the Holley tbi and performer rpm intake manifold with all the exhaust stuff. I have currently gotten rid of the tbi because I really could not get it running right with tbi and I was not burning the chip for my self so it really never got right. I went with an edelbrock 600 cfm carb and seem to do pretty decent. A computer should have no problem what so ever with this engine. Any specific questions?

 

Actually yes I have another couple q's. The distributor gear on the existing cc distrib, will it need to be changed to suit the cam in the 350HO? I'm not too concerned about the EGR since it has no feedback references on this ECM, and i've run the 305 without it without difficulty.
I know this is getting a bit fickle, but the accessory mount bolt holes, will they be the same? I still use the factory belt accessory setup, sans smog pump anyway. I might consider going serpentine later on though, so that's why I ask.
Thanks for the help, i'm printing out some of this so i'll have it when I get the engine.

 

the gear will do just fine and the mountnig holes for the brackets i am not sure because didnt they change the style of brackets 87? i am not sure about this one but i do know my surpentine belts out of my 92 work just fine with the heads.

 

i am sorry forgot to log in my sn