Building a 355 TBI, How much power should I make? - LS1TECH

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Building a 355 TBI, How much power should I make?

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Old 05-07-2006, 08:58 PM   #1
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Default Building a 355 TBI, How much power should I make?

I am in the process of rebuilding my 350. It is a 2 Bolt from an 87-91 Full Size Truck. I am using an eagle cast crank(3.48"), eagle connecting rods(5.7"), hyperutectic flat top pistons (.030) and a comp cam with stock heads & rebuilt valvetrain with 1.5 ratio rockers. I should be around a 9.4 / 9.5 to 1 compression ratio and am using the TBI from the pickup it is going in. The Cam Card is as follows;

Intake Exhaust
Lift Lift
.447 .462

210 218

Lobe Separation Angle

I am putting this engine in my 95 Chevy C1500 Pickup 2WD, 4L60E, and 3.08 rear end gears. I am not concerned with making max power but I would like to know what it might make.
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Old 05-07-2006, 09:40 PM   #2
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You probably know this but you must tune the crap outta a TBI system to reap all of the benefits of your new setup. Not tryna be an *** but I have seen to many people completely disregard chip burning in TBI setups. is the best place to get help with TBI chip burning.

You should be putting out some good power, TBI will get the beast movin' from a stand still.
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Old 05-07-2006, 10:14 PM   #3
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youre not going to make that much power, ive been down the tbi road will make decent though, id guess around 245 at the crank if youre lucky. Its the tbi and the shitty stock heads that hold you back..those tbi heads are the worst flowing heads ever.i had a similar setup 355, cam, headers,intake,"chip",etc had good torque but not a whole lot of power. I will agree with the above, thridgen is a great source of any and all things tbi and tpi. Your going to have to do something though with that 111 lobe sep, i dont think the stock chip will even run it , it may but i dont think so.
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Old 05-10-2006, 06:47 PM   #4
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I went to third and got some more help there. My 111 degree LSA is near my stock LSA of 110 on my 1995 engine. My TBI is from a 1995 c 1500 truck so I think it will work good with the computer.
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Old 05-17-2006, 07:06 PM   #5
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Ok, you will need some cop car injectors(68 lb/hr), adjustable FPR, and definately a chip but I see 250-260hp out of that...tuned to the max. You have 210 stock then you bumped compression a full point and added a nice size cam so....but you will need to get the exhaust done, open up the intake system to make it.

You will need a chip to run it...the stock cam is like 179/194 plus TBI engines are particularly picky with vacuum, MAP pressures, etc. TBI engines are very picky.

Hope this helps.
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Old 05-18-2006, 01:08 PM   #6
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These guys are pretty close on the estimates. TBI is a horrible setup for making power. Its a great setup for torque motors though...
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Old 05-18-2006, 01:20 PM   #7
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What intake manifold are you going to run? Stock?

Consider an aluminum carb manifold (like an Edelbrock Performer from Ebay) with a TBI adapter plate. Some power (and weight savings!) to be found there.

Sounds a lot like the motor I put together in my '79 Z28. I bought a crate L05 GM motor (92-93 Caprice, plain jane all the way), put a CompCams 302 in it (210/220 .480 lift), Edelbrock Performer manifold, Holley TB adapter plate, Holley TB, Painless harness, MSD Pro Billet distributor, and a '747 ECM. I haven't driven it a whole lot (car needs a lot of body work), but it runs just fine. Sounds good through the Hooker headers and Flowmaster H-pipe exhaust (LOL, there's nothing quite like an old Camaro with Flowmasters). I have tweaked the chip some with Tunercat software, but not a lot.
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Old 01-14-2007, 11:40 PM   #8
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Have you seen any of those TBI heads first hand? They are absolutely pathetic. I wouldn't run those on ANY motor I was building- period. They leave so much power on the table.

Ben T.
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Old 01-15-2007, 02:39 AM   #9
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under 4500 rpm those heads will not be a restriction at all.

for more info a great website is:

you're not looking to spin the motor to the moon and since it's a truck, torque is where it is at, so check out that site....has a dedicated performance board with tons of stickies for TBI motors and chip vendors.
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