If I start out with a 305 tpi, do I only need to change the block?

what else needs to be changed?
heads?
injectors?
sensors?
??????????????????

 

305 TPI intake setup will choke the crap out of a 400 unless you want a torkie engine win minimal HP. you would want larger TPI parts, bigger injectors, asjustable fuel pressure regulator, chip. A good exaust system would help. SLP 1-3/4 headers.

------------------
-Tas
'89 Formula WS-6
[soon to be Performace Red =) ]

305, TBI, auto, 14x3 chrome flat based open element with K&N, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Super GRK_Taz World
EFI & Intake Options
AOL IM: superGRtaz
ICQ 82881207

 

At the bare minimum to get it running, nothing. However, for it to run halfway decent you need bigger injectors and a 350 (or custom) chip.

That's just to get you by though...

------------------
87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224 .495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\Flowmaster catback. Coming Soon(?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - 161,000 miles, !cat, 9" K&N

 

that's why I said "want" and not "need".

 

The 305 heads choke a 305. You could use them on a 350, but by the time you got it to run right, you could have started with proper heads and done it cheaper and sooner.

Since you asked about just changing the block, 305's & 350's have different harmonic balancers and knock sensors. However, 305-type 19 lb injectors will work with a 350 if the fuel pressure is bumped up.

But, again, if you just want it to run...