randy111

iTrader: (1)

Hello everyone. I have been looking throu alot of the threds on here regarding motor swaps. My current setup is a 1991 Camaro with a LO3 305 TBI, automatic 700R4 trans. I have read alot about the 305 LO3 to 350 LO5 TBI swap. Extreamly usefull information in those threads. has answerd most of my questions. I do have a few as i am not using a LO5 motor, i'm just using the ECM and TBI and Intake from it.

To explain more, My brother pulled his 1969 Chevy 350 out of his Camaro adn dropped in a newly built 383. The motor is a orginal 350, It has been punched .60 over, Cammel hump heads, Dished pistons, 4bbl carb stock crank. the cam is a monster, Lift: .576''/.600'' Duration: 294°/300°.

This is the parts i have and what i'm going to attempt to do.
I have a ECM and Intake manifold off of a 1990 chevy caprice. It had the LO5 350 in the car. On top of the Intake manifold there is a 454 TBI witha 1 1/2 in spacer plate. My plan is to mate up the 1990 intake and 454 TBI with the 69 350. Re-tune the ECM to make it all work. (eayser said than done i know) I plan on compleatly tearing down this motor to bare block. doing a full rebuild on it and changing out a few parts. Have a machine shopo hone and check the block, have the heads compleatly rebuilt, have the crank turnd, new barrings, gaskets whole works. I'll be installing most of it but i will need a shop to do the machine work. I have a faily good understanding of how the motors work, and what not but some things i dotn quite have a grasp on so forgive me if some of my questions sound a little dumb.

A few things i do know i will need to fix or change.

First is, The intake manifld will need some modification the the bolt pattern to allow it to bold up to the old premitor bolt style heads. I have been told this is a very simple mod and will have no problems running it like this. I will most likely have the machine shop do this for me when i have the heads adn block work done.

Seccond thing I konw i need to address is fuel pressure and delivery, I plan on running a TPI pump wiht a F.P.R. and guage this should in theory be all i need to feed the TBI all the fuel it will require.

Re-tune the ECM obviously, kinda a no brainer here. this will be trail and error till i right.

Replace the old vacume controlled Distributor with a computer controld one, Question here.... Can i use the Distrubitor off of the 1990 Caprice LO5 350? or will i have to use a diffrent one?

Big question here i have is What do i do about Knock Sensor? The 1990 ECM is gonna want one, the 69 block dont have one. How do i get around this? If i understand the way this work correctly, the ECM is going to want to use the knock sensor along with the O2 sensor to adjust the timing while driving correct? How would i address this issue?

Saddly here i have to pass emissions, so i'm required to run the somg equpment. If not for that i'd Leave the motor exactly as it is and run the carb. But I would automaticly fail emisions inspection with a carb on it since it was not a option for my year camaro I have all the smog equipment needed to put on the motor from my LO3, and the headders that are on the 69 350 have the air lines in them, tho they are just capped right now, the fittings are there to hook it up. i just have to bend up my own tubing to make it work since its one fitting in each headder insted of the factory style 4 line. plum that into the SOMG and hook up the EGR system as well.

I'm pretty sure that it gonnna be a dam near impossable task to get the ECM to work with that cam my brother has in the motor now. I was thinking i was gonna go with a LT4 type cam. It will make it alot easer to tune from what i'm reading and the computer will have a eayser time making the car idle if i understand things correctly, Even the LT4 i might have a difficult time tuning. I defnitly want to go with something a bit less agressive that what is in the motor now.

If i take out the larger cam, and drop in a smaller one, Will i need to cahnge anyting with the springs, valves? Or sould it all work for me since i'm going smaller insted of larger on the cam size? The motor is a roller motor already so its setup with a roller cam.



Thats about where i'm at right now aside from swapping the 700R4 for a T56 after the motor is compleatly finished.

If you are wondering why i'm going with a TBI setup, I have three reasons for this, First is I have most of the TBI stuff to feed a 350 motor. Seccond is, I currently have a TBI setup in my car so doing a 305 to 350 TBI swap in it self is fairly simple, IF i was using the correct year motor.... and i also wont have to deal with swapping out wire harnesses and all that stuff. Third, I'b been running tbi and honestly its simple and easey to work on, i dont mind it. And to be honest I'm not trying to get the horsepower numbers that would make a TBI system inadiquate to feed a motor fuel. For wht i'm aiming for as far as Horsepower and Torque #'s, a 454 TBI is mroe than plenty to feed the motor fuel. I'm shooting for 350 HP, I'll take what ever it ends up beeing, but i'm hopeing to get at least 350 out of it.


So questions, comments, Suggestions? Any input would be awesome.


Thanks,
-Randy-

five7kid

iTrader: (14)

The other option for the intake is to use a carb style with a TBI adapter.

Something tells me the ECM isn't going to like that cam, regardless what else you do.

Camel hump heads and dished pistons - compression is going to be down in the dirt.

Knock sensor - from the Caprice LO5. Distributor - your 305 unit will be fine.

You didn't say what you're doing for exhaust, but replacing everything from the exhaust ports at the heads to the tailpipe tips at the rear bumper is the only way to go.

randy111

iTrader: (1)

Camel hump heads and dished pistons - compression is going to be down in the dirt.

I dont know the exact specs on the pistons, but My brother told me he's running 9.1 : 1 compression in the motor. When they had the motor rebuilt he said he got dished pistions for it agin but they were not the same as the factory ones.


You didn't say what you're doing for exhaust, but replacing everything from the exhaust ports at the heads to the tailpipe tips at the rear bumper is the only way to go.

The motor has Headders on it, I'm going to run dual 3" exaust all the way back with a 3 1/2" H pipe. I'm gonna run the H pipe where the factory "Y" pipe would normaly be run up by were the motor and trans bolt togather. have not picked out witch brand i'm going with for cat's yet. I'll fab up the exaust my self, I'm going to be removing the back seat of the car any way, i'm gonna cut up the floor pan just behind the drivers seat and make some room under ther for the cat on the driver side so i can keep ground clearance. I have a brace that will run from the SFC's to the trans so can hook on exaust hanger there and i'll weld in more mounting points as needed. I not 100% on how i'm gonna run the exaust yet thats gonna be a get it up on the lift and kinda play it by ear adventure.


Thanks for the suggestions. Thats the kinda stuff i'm looking for

-Randy-

Atilla the Fun

Those heads will need hardened valve seats to run unleaded gas. You will need a milder cam. If you're going Hydraulic non-roller, About the biggest I'd dare try with your electronics is a 214/224-112 442/465 cam, and after initial run-in with 1.5:1 rockers ans stock-type valvesprings, then switch to 1.6:1 roller rockers with springs such as Crane's 99848 or Comp's 981.

five7kid

iTrader: (14)

If those headers were for the '69 Camaro, they won't fit in a 3rd gen chassis.

Atilla the Fun

Way way way overkill on the exhaust. Any common aftermarket single 3" exhaust will suffice, and duals really don't fit. Basani makes true duals for the '98-'02 Camaros, which use the same style rear suspension.

randy111

iTrader: (1)

Thanks for all the input guys. Thi is exactly what i'm looking for. About the rockers, What is the binnifit of running diffrent size druing breakin? I'v never built and broke in a motor before. just wondering exactly what it helps to do?

As for the headers, yea i totaly dint even think about them not fitting. So yea that will be a problem. I'll have to purchase a new set that will work for me.

thanks for the input, Keep it coming. This is da info I need.


-Randy-

five7kid

iTrader: (14)

Reduces the load on the cam lobes.

Atilla the Fun

nearly all factory-GM SBC rockers are 1.5:1, supposedly. In checking them, the earlier ones are actually closer to 1.45:1. If the slot is long enough to not hit the rocker stud, they're great for cam run-in. Stock rockers are usually safe for a 0.465"-rated cam.

randy111

iTrader: (1)

Ok, that makes since with the rockers. LOL see thats why i like this sight. Lots of very usefull information. I will have to see what it has in it and figure out what i'm gonna run after the rebuild.


After doing alot more serach and reading up. I agree, I'm gonna go with the factory style exaust on the car. Still have not yet decided on brand, but i'll do a Y pipe setup on it, and a dual out muffler.

I should be fabricating my own Sub frame connectors this coming weekend, and the roll cage inside the car as well. Hopefully i can get that all buttoned up and finished.

I did find out something else. I have to do some more reading up on it this to find out for sure, but I belvie the other throttle body i have is not a 454 as i was told. It looks to be a 305/350 TBI unit but it as been punched and new butterflys installed. the bore is now 50mm bore on each barrel. anyone know the stock Size of these and or the bore size on the 454's? I was thinking if i do go ahed and use this punched TBI i will have to put larger inejctors in it. Can anyone give me a good recomendation what size injectors?


Thanks,
-Randy-

five7kid

iTrader: (14)

That's a TBI forum question.

randy111

iTrader: (1)

yea i was just thinking after i posted it i should go ask in the TBI fourm.


-Randy-