I am about to replace my 305 TPI engine(87' MAF setup) with a 350, staying with TPI in about a month. What parts need to be changed with it? I believe I have it all covered but want to be sure before going ahead with the swap . I will be using the knock sensor off the 350 thats going in(from a 87' mini-school bus with TBI ). I have a set of stock 350 TPI injectors off a 100k mile 91' Z-28 that worked fine before pulled but also currently have a set of 19lb Ford SVO's on my 305. Which ones should I use? The SVO's have about 10-15k on them and supposedly flow more than the GM version of 19lb, so both sets should be close to the same flow if I'm thinking about it correctly. Or should I splurge for a new set(budget is tight, prefer not to if possible).

The engine will be a Vortec head motor and I already have the Scoggin Dickey Vortec intake ready to go and a EGR block off plate. The chip tuning will probably be done after the swap, unless I should get a baseline 350 chip done first deleting the EGR, cold start injector, etc. Should the ESC module be replaced too? TIA.

 

You may also need to replace the ESC module. Reportedly, the output levels to the ECM are different, but I have not personally verified this.

Stay with the 22# 1991 injectors if they are still working. Even though they are Multecs, the flows should be closer to what you need with a basically stock 350 PROM.

Are you planning on using the 1987 MAF ECM, or changing to a later (S/D) ECM?

 

Thanks for the reply.

I plan to keep the 87' MAF ECM for the forseeable future, haven't contemplated converting to SD yet. Do you think the ESC module would make a big difference either way? I'll go with the 22# injectors although they have been sitting for over 2 years, they were known to be in good working order when pulled and I purchased shortly thereafter from a local with some other TPI parts he no longer needed as he upgraded his cam and TPI intake setup.

 

It depends upon the future of the engine too. If you'll keep the stock 350 for a while, I'd say go with the smaller injectors, and increase the pressure a few PSI. Secondly, I'd spend the $80 to get them flow matched. You'd be amazed at how much one poorly flowing injector will mess the works up.

 

Check out TPIparts.net they have a nice article on 305 to 350 TPI conversion. It is pretty informative.