305 Vortec heads with TBI ?

305 Vortec heads with TBI ?

Postby webcat [OP] » August 29th 2009, 6:10pm

i'm working on a 1996 Express van 305 Vortec 4l60E

I have a 305 Vortec that i'm planning on putting a TBI intake on but i'm not sure about what prom , fuel injectors or fuel psi to use
eventually i'll get a custom chip burned but i want to get in the ballpark
All my TBI parts came from a 1995 Full size van that had a TBI 350 and i'm assuming my Vortec 305 is simular to the TBI 350 (power wise and fuel consumption wise)
So what i'm thinking is that my 305 Vortec should run good just by using all the parts from the TBI 350 , meaning the prom, the 55LB 350 TBI fuel injectors , and the TBI fuel pump that had a psi of 10psi
What do you think? Will this thing run with the 350 prom , 350 injectors and 350 fuel pump?


i'm working on a 1996 Express van 305 Vortec 4l60E
and i want to put this intake on
Attachments
vortec_intake.jpg
vortec_intake.jpg (71.19 KiB) Viewed 1432 times
Last edited by webcat on August 30th 2009, 11:48am, edited 4 times in total.
Original Poster [OP]
User avatar
webcat
Section Moderator
Section Moderator
Firing on 3 Cylinders (L3)
Firing on 3 Cylinders (L3)
Years of Membership: webcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full years
Posts: 2304
Topics: 252
Joined: September 2008
Gender: Male
Alias (AKA): Larry aka Rambo
Van Make/Model: Chevrolet Astro
Extra Info: g10 5.7L vortec

  • Similar topics
    Replies
    Views
    Author

Re: 305 Vortec heads with TBI ?

Postby jeff's93astro » August 29th 2009, 10:36pm

the chip and parts from the 350 should work fine on the 305 cause the only difference is the bore is just a little smaller
88 Silverado 5.7L RWD 284,000 miles (going 383 soon)
93 Astro CS 4.3L RWD 230,000 miles (89 Astro 4.3)
ImageImage
User avatar
jeff's93astro
Firing on 1 Cylinder (L2)
Firing on 1 Cylinder (L2)
Years of Membership: jeff's93astro has been a member for 5 full yearsjeff's93astro has been a member for 5 full yearsjeff's93astro has been a member for 5 full yearsjeff's93astro has been a member for 5 full yearsjeff's93astro has been a member for 5 full years
Posts: 1111
Topics: 53
Joined: July 2009
Location: Georgia
Gender: Male
Van Make/Model: Chevrolet Astro
Extra Info: CS 4.3L V6 RWD

Re: 305 Vortec heads with TBI ?

Postby astro355 » August 30th 2009, 1:11am

But its going to run very rich. Even if the only difference between the 305 and 350 was the bore, you might as well attach a bucket of the tailpipe to catch the extra fuel. The ecm can only lean out the fuel so much, it won't be able lean it out enough.

What I would be more curious about is the cams in the 305 and 350, that's were the real differences will be.

What year was the van the 350 came out of?
Diagnose 1st, never be a parts changer!

355 small block chevy w/ modified 700R4

Image
User avatar
astro355
V8 Swap Achievement
V8 Swap Achievement
Firing on 4 Cylinders (L6)
Firing on 4 Cylinders (L6)
Years of Membership: astro355 has been a member for 6 full yearsastro355 has been a member for 6 full yearsastro355 has been a member for 6 full yearsastro355 has been a member for 6 full yearsastro355 has been a member for 6 full yearsastro355 has been a member for 6 full years
Posts: 5488
Topics: 57
Joined: May 2008
Location: Cleveland, OH
Gender: Male
Year: 1989
Van Make/Model: Chevrolet Astro
Extra Info: 355 V8 700R4

Re: 305 Vortec heads with TBI ?

Postby webcat [OP] » August 30th 2009, 4:53am

The van i got all my TBI parts from was a 1995 and i have a PCM 16197427 BHMC with stock prom and engine wire harness for a 1995
I'm trying to set my Van up like a 1995 model were they have the TBI intake and the 4L60E trannee the only difference is i'll have vortec heads.
Last edited by webcat on August 30th 2009, 5:23am, edited 2 times in total.
Original Poster [OP]
User avatar
webcat
Section Moderator
Section Moderator
Firing on 3 Cylinders (L3)
Firing on 3 Cylinders (L3)
Years of Membership: webcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full years
Posts: 2304
Topics: 252
Joined: September 2008
Gender: Male
Alias (AKA): Larry aka Rambo
Van Make/Model: Chevrolet Astro
Extra Info: g10 5.7L vortec

Re: 305 Vortec heads with TBI ?

Postby webcat [OP] » August 30th 2009, 5:12am

astro355 wrote:But its going to run very rich. Even if the only difference between the 305 and 350 was the bore, you might as well attach a bucket of the tailpipe to catch the extra fuel.


You know at first i was thinking that same thing so i was going to put 40 LB 305 TBI injectors in it
but the more i thought about it the more i was thinking the 55 LB 350 injectors would work
If i was trying to put 350 TBI injectors on a normal 305 TBI i could see it running rich but i'm thinking the vortec 305 may use alot more fuel then the older 305 TBI engines

The reason i beleive the 55 LB TBI injectors will work is because the 305 Vortec is 220 HP and the 350 TBI engine is 185 to 195 HP
So i'm thinking the 305 vortec probally uses just as much or more gas thaen a 350 TBI engine
Original Poster [OP]
User avatar
webcat
Section Moderator
Section Moderator
Firing on 3 Cylinders (L3)
Firing on 3 Cylinders (L3)
Years of Membership: webcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full years
Posts: 2304
Topics: 252
Joined: September 2008
Gender: Male
Alias (AKA): Larry aka Rambo
Van Make/Model: Chevrolet Astro
Extra Info: g10 5.7L vortec

Re: 305 Vortec heads with TBI ?

Postby astro355 » August 30th 2009, 10:08am

The base fuel maps for those two engines are completely different. The vortec 305 doesn't use more gas, the heads flow better thus creating more HP. Comparing the HP output of those two engines is not an indicator as to how much fuel each engine uses, there is nothing that can be compared there.

Back in my firebird days, we talked about doing this kind of swap. We were curious as to if a 350 TPI engine could run on a stock 305 ecm. Luckily, my buddy had a 88 firebird with a 305 TPI engine and my 89 firebird had a 350 TPI engine. Both cars were automatic, MAF, and had the cold start injector. We swapped the computers and the 305 engine ran way too rich as the 350 engine ran way too lean. The base fuel maps were just too different that adjusts made by the ecm involving IAT, ECT, TPS, etc could not alter the air/fuel ratio enough for each engine to run right.

I'm sure if you really want to put that 350 setup on a 305, it will run. Just not very good. The following will happen:

-you will waste fuel
-you will generate less power
-you will foul out your spark plugs
-you will wash out your piston rings
-and eventually have to change your oil
Diagnose 1st, never be a parts changer!

355 small block chevy w/ modified 700R4

Image
User avatar
astro355
V8 Swap Achievement
V8 Swap Achievement
Firing on 4 Cylinders (L6)
Firing on 4 Cylinders (L6)
Years of Membership: astro355 has been a member for 6 full yearsastro355 has been a member for 6 full yearsastro355 has been a member for 6 full yearsastro355 has been a member for 6 full yearsastro355 has been a member for 6 full yearsastro355 has been a member for 6 full years
Posts: 5488
Topics: 57
Joined: May 2008
Location: Cleveland, OH
Gender: Male
Year: 1989
Van Make/Model: Chevrolet Astro
Extra Info: 355 V8 700R4

Re: 305 Vortec heads with TBI ?

Postby webcat [OP] » August 30th 2009, 11:31am

Yep it looks like your right 355 , if i tried to run it using the 350 TBI prom and 350 fuel injectors it looks like it would run rich!

I was over at third generation.com and found a guy that put 350 vortec heads onto his 305 , he then put a carb intake on and a adapter for his TBI he also used a adjustable fuel psi regulator and i think he may have increased his fuel psi a little ( in his signiture it says BP and i assume BP stands for bumped fuel psi ) well anyways he said it runs like a bat out of hell with the stock tune but hes running everything with the 305 prom , 305 injectors and 305 fuel pump

So i was thinking if he can keep his stock tune and make it run good with all the mods he has i should'nt have a problem because i'm closer to stock

so if i put some 305 fuel injectors in my pod and a 305 prom chip in my PCM i think mine will be alright with the stock tune



Here's his signiture , he said hes running this with a stock tune 1991 305, World Class T- 5, McLeod Clutch, Converter Delete , Hooker 1 5/8 Headers and Y-Pipe, Heartthrob 3" Exhaust, heads 350 Vortecs milled to 56cc's, Comp 981 Springs, LT1 Cam, 1.6 Comp Rockers, Ultimate TBI mods, Bumped FP, .75" intake spacer, Injector Pod Spacer, Mobil 1, Edelbrock Performer RPM Air Gap Intake, BFG G Force T/A's, Eibach Sportline Springs
Original Poster [OP]
User avatar
webcat
Section Moderator
Section Moderator
Firing on 3 Cylinders (L3)
Firing on 3 Cylinders (L3)
Years of Membership: webcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full years
Posts: 2304
Topics: 252
Joined: September 2008
Gender: Male
Alias (AKA): Larry aka Rambo
Van Make/Model: Chevrolet Astro
Extra Info: g10 5.7L vortec

Re: 305 Vortec heads with TBI ?

Postby webcat [OP] » August 30th 2009, 10:03pm

I've ran into another article saying alot of people were'nt able to use the stock tune and also having problems tuning in general , however i think this may be from them trying to use big cams and other extreme mods!
I know once you get rid of the TBI cam your gonna have tuning problems .
I'm pretty sure the vortec roller cam should be alright though.
I 'm thinking of putting this off until mayby next year now and see what other info i run into.
Original Poster [OP]
User avatar
webcat
Section Moderator
Section Moderator
Firing on 3 Cylinders (L3)
Firing on 3 Cylinders (L3)
Years of Membership: webcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full yearswebcat has been a member for 5 full years
Posts: 2304
Topics: 252
Joined: September 2008
Gender: Male
Alias (AKA): Larry aka Rambo
Van Make/Model: Chevrolet Astro
Extra Info: g10 5.7L vortec


 
  • Related topics
    Replies
    Views
    Last post

Return to Engines

It is currently September 17th 2014, 2:31pm

Engines Forum
Engine Repairs, Modifications, Diagnostics, Tuning, Upgrading, Questions.
Moderator: chevy57bert
To create a new topic in Engines, click this button:
Previous topic Next topic
Recent Image Attachments
Attached by:
coult45
in Engines
Views: 221
Comments: 9
Date: Yesterday
Time: 2:21am
» Read last comment
Attached by:
Attached by: chevymaher
chevymaherchevymaher is online!
in Engines
Views: 306
Comments: 22
Date: Yesterday
Time: 1:33am
» Read last comment
Attached by:
Attached by: chevymaher
chevymaherchevymaher is online!
in Engines
Views: 306
Comments: 22
Date: Sep 15 '14
Time: 10:40pm
» Read last comment
Attached by:
Attached by: slavasz
slavasz
in Engines
Views: 244
Comments: 18
Date: Sep 15 '14
Time: 8:03pm
» Read last comment
Attached by:
Attached by: adam728
adam728
in Engines
Views: 231
Comments: 4
Date: Sep 11 '14
Time: 6:05pm
» Read last comment
Sponsors
 

Who is online

Users browsing this forum: 2Sheds_Jackson2Sheds_Jackson is online!, RECox286RECox286 is online! and 9 guests