350 power questions... (1 Viewer)

[cody c]

So Ive been thinking, what can i do to the TBI 350 to get a little more power without compromising on drivability and mileage too much. There seems to be tons of aftermarket support for the 350 but i dont have much expendable income..

Does anyone have experience porting and polishing stock heads, i was thinking of picking up a set of heads at the wreckers and putting some time into them, maybe throw on some cheap ebay bling rockers and aftermarket valves and springs but dont know a lot about this sort of thing. I have aftermarket plugs, wires and ignition on its way at the moment but i know realisticly this isnt going to do much.

Anyone with a bit of experience on cheap performance tricks or parts for these things?

Thanks.

Cody.

 

[liljlandon]

Do you want torque or ponys?

 

[Gumby]

Vortec heads are an easy power upgrade. Pretty cheap too. Make sure you find a set with no cracks. They tend to crack between the center cylinders from the coolant passages to the bolt holes.

 

[brokenparts]

how much is your budget? The stock computer doesnt like alot of "upgrades" so you have to be careful that you dont overdue it unless you are willing to invest into a upgraded computer.

 

[cody c]

Vortec heads are an easy power upgrade. Pretty cheap too. Make sure you find a set with no cracks. They tend to crack between the center cylinders from the coolant passages to the bolt holes.

Is there any mods to use these with a TBI setup or is it a straight bolt on process, i would like to try a bit of port and polish on heads to get a bit of experience, can you reccomend a grinder kit or source for more info?

As far as torque or pony's goes, well the 80 wont really see any trailers although it is a possibility, and im not into making a rocket out of it, i will probally go to 35's next year and it will still see city driving and trips up to edmonton (about 200 miles) and back. So mostly im looking for a smoother running motor with more power for passing and to compensate for 35's ( i dont plan on gears any time soon $$$ ) without hurting economy too much

(ya i know i want all the pros and none of the cons)

maybe 4 or 5 hundred bucks or so into it in the new year is the budget.

 

[brokenparts]

Is there any mods to use these with a TBI setup or is it a straight bolt on process, i would like to try a bit of port and polish on heads to get a bit of experience, can you reccomend a grinder kit or source for more info?

As far as torque or pony's goes, well the 80 wont really see any trailers although it is a possibility, and im not into making a rocket out of it, i will probally go to 35's next year and it will still see city driving and trips up to edmonton (about 200 miles) and back. So mostly im looking for a smoother running motor with more power for passing and to compensate for 35's ( i dont plan on gears any time soon $$$ ) without hurting economy too much

(ya i know i want all the pros and none of the cons)

maybe 4 or 5 hundred bucks or so into it in the new year is the budget.

vortec heads is a good upgrade but you'll need to use a vortec style intake as well. You can either use the tbi vortec intake or a 4bl vortec with and adapter. Thirdgen.org is a great site to learn a bit more on tbi stuff.

by the way... the tbi heads arent worth the time to port and polish... there's not a lot you can do with them. Most will tell you that they were one of the worst GM heads produced.

 

[cody c]

Thanks MR Brokenparts!
Any experience with aftermarket rockers or valves and springs? like these?

eBay Motors: 1.6 327 350 383 CHEVY ALUMINUM ROLLER ROCKER ARMS 7/16 (item 270303202458 end time Nov-24-08 17:43:43 PST)

And what year would i find a TBI vortec intake manifold on? or any decent cheap aftermarket manifolds to suggest? I see summit has some affordable/ fancy looking stuff.

Thanks!

 

[cody c]

so, ive been doing a bit of reading and im starting to think im a hopeless idiot.

Can i still use TBI with vortec heads and edelbrock manifold : Edelbrock 2116 - Edelbrock Performer Vortec Intake Manifolds - summitracing.com

or is this pointless?

 

[BionicCruiser]

i port & polished (port matched really) my 350 LT1 heads. i got an abrasives kit for $50. it had instructions with it. as long as you aren't going over board with the porting, you can do it. the port match was easy and relatively risk free. i did put on similar roller rocker like you mention too. i wouldn't look for big horse power gains with these basic mods, but it can't hurt and it isn't too expensive.

edit-swapping around heads, i have no experience. my computer handled the basic mods with no problem, but it's a SFI engine too.

 

[brokenparts]

i port & polished (port matched really) my 350 LT1 heads. i got an abrasives kit for $50. it had instructions with it. as long as you aren't going over board with the porting, you can do it. the port match was easy and relatively risk free. i did put on similar roller rocker like you mention too. i wouldn't look for big horse power gains with these basic mods, but it can't hurt and it isn't too expensive.

edit-swapping around heads, i have no experience. my computer handled the basic mods with no problem, but it's a SFI engine too.

yeah, the lt1 engine/computer and a TBI 350 are two different animals.

 

[brokenparts]

Thanks MR Brokenparts!
Any experience with aftermarket rockers or valves and springs? like these?

eBay Motors: 1.6 327 350 383 CHEVY ALUMINUM ROLLER ROCKER ARMS 7/16 (item 270303202458 end time Nov-24-08 17:43:43 PST)

And what year would i find a TBI vortec intake manifold on? or any decent cheap aftermarket manifolds to suggest? I see summit has some affordable/ fancy looking stuff.

Thanks!

I dont have any experience with those rockers. Stock ratio is 1.5 and you need to make that the stud size is correct. I bought a decent set from summit. Basically just an bolt on upgrade. The TBI/vortec intakes are an aftermarket item... Most big suppliers carry them though. Make sure you check your state on whether or not you have to run your egr junk or not. They make intakes with and without it.

 

[brokenparts]

so, ive been doing a bit of reading and im starting to think im a hopeless idiot.

Can i still use TBI with vortec heads and edelbrock manifold : Edelbrock 2116 - Edelbrock Performer Vortec Intake Manifolds - summitracing.com

or is this pointless?

You need to make sure that the intake matches the heads. Vortec heads have a different bolt pattern. You can use a vortec intake meant for a carb and then run a tbi adaptor for it but you'll have to fab up your own linkage for the throttle and such.

Here's an example of the adapter:

http://cgi.ebay.com/ebaymotors/Holl...012QQitemZ220317972633QQrdZ1QQsspagenameZWDVW

 

[BionicCruiser]

yeah, the lt1 engine/computer and a TBI 350 are two different animals.

can you flash the prom on the TBI to adjust for a port match? does even it have a prom chip? my next project i am thinking of doing a TBI, so the info will help me too. i haven't done the research yet.

 

[brokenparts]

can you flash the prom on the TBI to adjust for a port match? does even it have a prom chip? my next project i am thinking of doing a TBI, so the info will help me too. i haven't done the research yet.

The best solution for TBI controlled units is use the ecm offered by dynamicefi (aka the ebl). Sixty is the resident hero on the subject... hopefully he'll chime in.

I'm using the ebl from dynamic efi and it is a great solution for tuning systems like the tbi and can even run systems like mpfi...

here's the link... good info if nothing else:

DynamicEFI

 

[sixty]

Not much you can do to the TBI for $500 without ditching the system. Even in the stock configuration the ECM could use some tuning mods since the software is designed to be emissions freindly.

The best way to go about building a TBI is to learn to tune. You can either buy all the chip burning equipment for around $200 or get an EBL for about $300. Once you learn to tune, the sky is the limit. then you can do all the standard small block mods for power.

I bet I probably have $1500 into my TBI system not including all of the TBI parts. Seat of the pants, I'm probably making a very use able 350-400hp.

 

[sixty]

can you flash the prom on the TBI to adjust for a port match? does even it have a prom chip? my next project i am thinking of doing a TBI, so the info will help me too. i haven't done the research yet.

Yes you can burn a chip to change the fueling for the port match. This will require data logging and making the required changes to the program. The problem with the stock TBI ecm is that it only samples data less than once per second. This means it can take forever to get useable information for tuning. with the EBL mentioned above the sampling rate is over 30 time a second so it really speeds up tuning. It can also auto learn the fuel map just from the O2 sensor data. It is defiantely a great way to go.

As far as porting the heads, its pretty much polishing a turd and you have to be real careful with the swirl port design as I have heard its pretty easy to actually reduce flow. You are much better off getting a set of vortecs or a good set of torquer heads or even some nice aluminum ones. Then you want to skip the TBI manifolds all together and use a standard squarebore intake with an adapter to the throttle body. These will flow alot better.

I have been reading about all of the 400hp mods that can be done to the new 2nd gen 5.3's and it sounds cheap and easy. I have no experience with these systems but it does sound like a decent way to go. I doubt that they have the low end from a well built TBI system though. If I didn't already have a TBI in my ring I might have tried this route. My TBI stroker has alot of low end grunt, the only thing I wish I had now is a Big block or a roots blower .

Check out the forums over at 3rdgen.org. Those guys have built some pretty awesome TBI's.

 

[sixty]

One other thing, probably the best bang for you buck mods would be heads and cam. The stock cam is very anemic. You can easily add 100hp just with heads, cam, tuning, bored thorttle body and exhuast.

 

[brokenparts]

see I told you sixty was the man...

Hey when you step up to a big block I get first crack at that stroker.

 

[sixty]

Hey when you step up to a big block I get first crack at that stroker.

By the time I get the $$$ to upgrade, gasoline engines will be obsolete... but I'll keep you in mind

 

[cody c]

well, a little update..

i contacted summit and they found a edelbrock performer manifold and adapter that would work for vortech heads and TBI.

And then on Tuesday the wife wrote the 80 off ( I have to talk to the insurance adjuster to be sure but the front end is mangled, the frame is twisted, and apparently it was making a bad noise in drive but not in reverse tranny=fked).
However the good news is the wife walked away shaken but uninjured, and is stoked on how it performed in an accident, so it looks like we will be shopping for another one soon, possibly an equivalent from the states, or i may try and sweet talk her into a RHD hdj81 depending on how the money thing works out.

Either way i would still like to keep this thread going as so many cruiser enthusiasts are going to the SBC, and its great to get so much helpful response.

Cheers!