jimmy2s83

OK,

So I will be swapping out the LB9 out of the 89 Firebird due to knocking. I have a 300HP 350 that will be going in. The 350 is fairly comparable to the LT1 in the area of specs but is an older block with perimeter bolt heads. Getting an 85 TPI lower intake to make fitment easier than redrilling the stock intake to make it fit.

So I am wondering if the stock injectors from the LB9 would be sufficient or if a larger injector would be required. If a larger injector is required would there be any ECM changes required?

Tried to search the forums but really couldn't find anything relating to upgrading the injectors. I'll also be installing a set of Flotech headers while the engine is pulled.

If any additional information is required just let me know and I'll get it posted.

midias

Put the floteck headers in the trash can

KMdoza7

iTrader: (1)

so you are swaping a 305 to a 350. the 305 uses 19 lb injectors and the 350 uses 22 lb injectors. what are the casting numbers on your heads

jimmy2s83

Heads are World Products. I can get specs on them if you wanted them.
The 350 is a Jasper engine rated at 300HP. Had it in a 79 Camaro for about 10K miles. It was carbed at that time and I'd like to keep with the TPI in the 89 bird. Also I gave the Carburator to my brother so I'd have to get another one anyways.

From the sounds of it I shoud get at least 22lb injectors. My concern is also that the stock L98 wasn't much more HP than the LB9 in 89 when it was backed by a 5speed. From my research I see that the 5speed 305 received a larger cam which bumped the HP to around 220-230 depending on your source of info.

With a 300HP 350 would 22lb injectors even be sufficient?
Also does the ECM required any mods or changes to account for larger injectors?

Thanks in advance!
Really hoping to get everything figured out up front.

KMdoza7

iTrader: (1)

yes 22s should be fine.
as for the ecm it will be fine also since its a maf and a little more forgiving. i see you have a t5. there were no 5 speed 350 cars so if you have driveability issues you might want to get your memcal reprogramed. message member Tuned Performance. he can burn a chip at a good price

KMdoza7

iTrader: (1)

yes 22s should be fine.
as for the ecm it will be fine also since its a maf and a little more forgiving. i see you have a t5. there were no 5 speed 350 cars so if you have driveability issues you might want to get your memcal reprogramed. message member Tuned Performance. he can burn a chip at a good price

jimmy2s83

Thanks!

I have talked to him and he gave me some good advice. I am going to get the memcal done to make sure everythig is good to go.

He also mentioned the Knock Sensor for the 305 and 350 were different. Fortunately I had one for a 350 already so that worked out great!

From what I have looked up and have been recommended it would probably be best to get some 93-97 LT1 injectors since they are 24lb and the 22lb while they would get the job done would be under more stress with the larger fuel demands of a 300hp engine. This way if I decide to bump up the HP a little more in the near future the injectors would already be set anyways.

Hopefully I'll be cruising when the snow an frigid air finally leaves us!

Thanks again for all the help.

Tuned Performance

iTrader: (92)