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Discussion Starter #1 (Edited)
Tpi 350 with 305 heads

I just got a TPI 305 off craigslist. It looks to be in good shape and it is not locked up. I am wanting to build it up for my landcruiser. I have confirmed that it is a full roller set up. Before I start disassembling it to change the cam and all the gaskets I want to do a compression check. I;ve done compression tests several times before but they have all been on motors that haven't been sitting for a while. The guy I got the motor from wasn't sure how long its been sitting but it has been at least 2 years. What I ultimately want to know is should I change the oil, and put something in the cylinders to prevent it from being damaged? Im scared that the cylinder walls are dry from sitting and i might scar them when doing the compression check, also if i put oil in the cylinders then I might not get the best reading. All I want to know from the compression test is if the rings are leaking. I plan to change the head gasket and do a leak test on the valves so Im not worried about if it is loosing compression through a bad valve or bad head gasket. Or should I not worry about the compression test at all since I will be pulling this motor almost completely apart anyway? thanks.
 

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Discussion Starter #3
Keep the TPI and dump the 305.
If you plan to build a small block dont bother with the 305 same performance parts on a 350 will gain more power.
I actually want to keep the 305, it is a good little motor and it has a factory roller cam in it, my current 350 was made before 86 so id have to retrofit it. The 305 makes good torque and I dont care about having high horsepower numbers.
 

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a little light oil wont hurt anything, but will throw off your compression readings, one of the tests for bad rings is to compression test once, the compression test again with oil in the cylinders to check for ring wear. if it comes up significantly then you have worn rings.

meh, i hate pulling engines twice. i'd prolly pull the pan, look at the cylinders from the back side and check the bearnings. if the cylinders arent scarred up and the bearings look good run it. if it's all full of sludge, or there's damage then your gonna have to tear into it anyway. throwing a new stock oil pump (dont need a high volume pump if not building a performance engine), pickup screen and rear main, pull the timing cover and maybe throw a timing set at it- stock came with plastic gears and they may break seeing as how it was sitting a long time. finally a water pump and valve cover gaskets. these things wont hurt either because they are some of the things that don't cost much but usually require pulling the whole engine to change. couple hundred bux now could save you an expensive tow bill later and engine replacement.

change the freeze plugs while your at it over to the deep brass ones. it will allow you to check out the condition of the cooling system, plus if the ones on the back of the block leak--- well you get the picture.
 

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Discussion Starter #5
a little light oil wont hurt anything, but will throw off your compression readings, one of the tests for bad rings is to compression test once, the compression test again with oil in the cylinders to check for ring wear. if it comes up significantly then you have worn rings.

meh, i hate pulling engines twice. i'd prolly pull the pan, look at the cylinders from the back side and check the bearnings. if the cylinders arent scarred up and the bearings look good run it. if it's all full of sludge, or there's damage then your gonna have to tear into it anyway. throwing a new stock oil pump (dont need a high volume pump if not building a performance engine), pickup screen and rear main, pull the timing cover and maybe throw a timing set at it- stock came with plastic gears and they may break seeing as how it was sitting a long time. finally a water pump and valve cover gaskets. these things wont hurt either because they are some of the things that don't cost much but usually require pulling the whole engine to change. couple hundred bux now could save you an expensive tow bill later and engine replacement.

change the freeze plugs while your at it over to the deep brass ones. it will allow you to check out the condition of the cooling system, plus if the ones on the back of the block leak--- well you get the picture.
Thanks.
 

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Ken, on the drivers side fuel rail there's a number that starts with 1708xxxx, or 1709xxxx in the middle of the rail. Not the one with letters that's easy to see. If you tell me I can identify it.

Check out a Comp 08-501-8. It is a great upgrade without losing drivability or mileage.
 

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Discussion Starter #7
Ken, on the drivers side fuel rail there's a number that starts with 1708xxxx, or 1709xxxx in the middle of the rail. Not the one with letters that's easy to see. If you tell me I can identify it.

Check out a Comp 08-501-8. It is a great upgrade without losing drivability or mileage.
I can get that. it will be a day or 2 cause im at school and the motor is at my house.
 

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A couple light squirts of oil in the cylinders will not hurt or give too much of a false compression reading. Since the engine has been sitting so long it would be good to oil the upper end to prevent any scuffing of the cylinders. Use some thing light like MMO or tranny fluid, crank the engine over by hand slowly to lube the cylinder walls and then compression test it. If you don't get it spinning fast enough you'll get false compression readings anyway. I like sjracers idea, put it on a stand and pull the pan to check out the bottom end. If its clean I've had good luck inspecting the oil pump gears and sanding the pump cover with 600 grit on a piece of glass if there's gear marks in it. Check the pressure relief valve and replace the spring and reuse the pump. You should easily be able to check timing gear and chain condition by turning the crank and watching the valve action. Rotate it both directions. Not sure about the plastic gear on roller motors (trucks don't use plastic gears) but on a low performance engine a morse chain is fine. I don't know what cam Mr. Willys is suggesting, but the 305 HO cam is not bad, 403/415 with a 115 degree lobe centerline. 202/206 duration at .050 lift. If its in that engine I'd use it. Part number is 14093643, 4 of those digits should be cast on the cam and may be one number off, so the cam may have a 3644 cast into it.
I looked up the cam Mr. Willys suggested, seems big for a 305. I'd be interested in his experience with it.
 

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I don't know what cam Mr. Willys is suggesting, but the 305 HO cam is not bad, 403/415 with a 115 degree lobe centerline. 202/206 duration at .050 lift. If its in that engine I'd use it. Part number is 14093643, 4 of those digits should be cast on the cam and may be one number off, so the cam may have a 3644 cast into it.
I looked up the cam Mr. Willys suggested, seems big for a 305. I'd be interested in his experience with it.
The OP has suggested that it is a roller motor. It could be easily identified by centerbolt valve covers, and a one piece rear main seal. The fuelrail number will allow me to identify it to within a 2 year period. Also, the cam quoted above is a very famous stock cam for the 305, but more importantly the L98 350. However, it was only used in the 87 5spd car in Camaro's. Can the OP tell if it had a flexplate, or flywheel? Different cams for different years, see here:
Third Generation Camaro Site
With identification it will be known whether he has one of the better, or anemic cams GM used in the TPI generation. If he has the better one like the one mentioned above maybe just a set of 1.6 roller rockers with an adjustable fuel pressure regulator will get the job done.
Funny that it was mentioned the Comp 08-501-8 seems big. Usually I'm accused of being conservative when it comes to cam selection. Cam selection for the SBC has more to do with stroke length than anything IMHO. A 305 is just an under bored 350, just like a 307 is an under bored 327. My choice would work well with a stockish TPI 305.
As for 350 vs 305? Vinny commented in the early part of the thread about just going 350. If a rebuild is in order then go this route. It costs more to rebuild a 305 than a 350. I know, I did it and would never do it again. I even used the GM cam mentioned above in an 87 IROC 700R4 combination and what a difference it made.
 

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With stock tuning, they respond well to more timing too. One of the best 'free' things you can do. I run 10-12 degrees advanced in all mine, usually no pinging with regular fuel but I run 89 just in case. Not sure I would go to the trouble of a cam swap in a 305 though.
 

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Discussion Starter #11
for a cam swap i did my research, and found out that the stock cam from an lt 1 fits in a 305. I plan to get it or buy the cam that came out of the 305 with the manual transmission. Im also thinking i might just run the cam in it and change it down the road. I did a compression check all the cylinders except number 8 are at 195 psi, number 8 was at 120. I put oil in 8 and got 200 psi, so it has bad rings most likely.

im not sure if it came with an automatic, it has a flexplate on it, but it is off a truck. the flexplate for the 305 has a 12.85 od and the c1500 has a flexplate that is 14.13 od. From the block code i know that it is a 1989 tpi motor, but the tpi system on it is 88 or older because it has the cold start injector.
 

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That LT1 cam is very close to the higher output cams that I linked. Sounds like maybe the TPI unit was swapped on it if the motor is an 89, but the TPI has cold start. The LT1 cam with come with an extra long cam gear index pin that must be cut if I remember right.
 

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That LT1 cam is very close to the higher output cams that I linked. Sounds like maybe the TPI unit was swapped on it if the motor is an 89, but the TPI has cold start. The LT1 cam with come with an extra long cam gear index pin that must be cut if I remember right.
Ya I new it would need to be cut. It is also a great budget item, because I could pick it up for under $100, through ebay or Oreillys. BTW the number that is on the drivers side fuel rail is hard for me to see and I plan to start disassembling the intake this weekend so I can get it for you then. Thanks for every ones help and information.

Does any one have a complete list of all the sensors needed for this swap? Every web page Ive found has different sensors, and I plan to get an aftermarket harness for it. The main sensor im worried about because im not sure what it is called is located between the spark plug holes for cylinders 1 and 3, it looks like a temperature sensor but there is already 2 temp sensors (cts and its) in the manifold?
 

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The OP has suggested that it is a roller motor. It could be easily identified by centerbolt valve covers, and a one piece rear main seal. The fuelrail number will allow me to identify it to within a 2 year period. Also, the cam quoted above is a very famous stock cam for the 305, but more importantly the L98 350. However, it was only used in the 87 5spd car in Camaro's. Can the OP tell if it had a flexplate, or flywheel? Different cams for different years, see here:
Third Generation Camaro Site
With identification it will be known whether he has one of the better, or anemic cams GM used in the TPI generation. If he has the better one like the one mentioned above maybe just a set of 1.6 roller rockers with an adjustable fuel pressure regulator will get the job done.
Funny that it was mentioned the Comp 08-501-8 seems big. Usually I'm accused of being conservative when it comes to cam selection. Cam selection for the SBC has more to do with stroke length than anything IMHO. A 305 is just an under bored 350, just like a 307 is an under bored 327. My choice would work well with a stockish TPI 305.
As for 350 vs 305? Vinny commented in the early part of the thread about just going 350. If a rebuild is in order then go this route. It costs more to rebuild a 305 than a 350. I know, I did it and would never do it again. I even used the GM cam mentioned above in an 87 IROC 700R4 combination and what a difference it made.
Not all center bolt valve covers and one piece seals indicate a roller motor. The trucks did not generally have roller cams until 1996. I just rebuilt my 1993 K2500 engine and it is a flat tappet cam with center bolt Valve covers and a one piece main seal. Most TBI truck engines are flat tappet cams.
Mr. Willys if your conservative than I am in the stone age! I installed an Edelbrock Performer cam in a 307 once, 420/442 lift and it sucked. Lost all kinds of manifold vacuum and of course ran badly at low RPM. On the other hand I had a 350 with a 447/447 327 hydraulic cam and it ran fine, a little lopey but not bad. I will add to your comment about stroke and say stroke, cubic inches and compression ratio all factor in to cam choice and its proper function in any given engine. Duntov cams were actually less lift than Chevys biggest cam at the time but had more duration and ran better.
The stock TBI flat tappet cams in 305 and 350 truck engines are for economy and torque at low rpm. A 305 flat tappet is a 350/384 lift cam and a 350 flat tappet is a 384/403 cam. This with stock 1.5 rockers. A carbed 350 cam is 390/410 and I installed a 398/420 lift flat tappet cam in the truck 350 I recently rebuilt. The engine now revs safely to 5000 rpms but still delivers good operating efficiency at cruise on the freeway 2100 @70 mph. So yea I am very conservative on cams, basically tailored to the use of the vehicle, gears and tire combo. 1993 K2500 with 3.73's and 285/75x16 (32's) tires
 

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Not all center bolt valve covers and one piece seals indicate a roller motor. The trucks did not generally have roller cams until 1996. I just rebuilt my 1993 K2500 engine and it is a flat tappet cam with center bolt Valve covers and a one piece main seal. Most TBI truck engines are flat tappet cams.
The OP originally posted a TPI 305 which all with centerbolt valve covers and one piece seals would be roller motors. Clear & concise comprehension may be required to not take my statement out of context.
The Comp 08-501-8 is a 50 state smog legal cam. As for the Duntov 30 30? I owned a stock 302 car with this cam. It's not anything like the one I've suggested, and has an advertised lift of .485. I can't think of any other bigger stick at the time except the one that came with the crossram option of the Z28.
 

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If the block is '89, the tpi is '87-'88 and it's got a truck flywheel, it's probably pieced together from who knows what. It could just be an '89 truck tbi 305 motor with the tpi stuck on top of it. Even if it is, there's a good chance the block has the provisions for the roller cam setup.
 

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Discussion Starter #17
If the block is '89, the tpi is '87-'88 and it's got a truck flywheel, it's probably pieced together from who knows what. It could just be an '89 truck tbi 305 motor with the tpi stuck on top of it. Even if it is, there's a good chance the block has the provisions for the roller cam setup.
I know for a fact it did come with tpi, i ran the numbers on it and I know that it has a factory roller cam too. Its not a truck engine.
 

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The OP originally posted a TPI 305 which all with centerbolt valve covers and one piece seals would be roller motors. Clear & concise comprehension may be required to not take my statement out of context.
The Comp 08-501-8 is a 50 state smog legal cam. As for the Duntov 30 30? I owned a stock 302 car with this cam. It's not anything like the one I've suggested, and has an advertised lift of .485. I can't think of any other bigger stick at the time except the one that came with the crossram option of the Z28.
True but he also stated it has some truck related parts on it also. You yourself said "the OP has suggested it was a roller motor. It could be easily identified by center bolt valve covers and a one piece rear main seal" My point was using strictly that criteria you could get a TBI truck engine that had a TPI bolted on and not really know for sure. Just saying. I know the cam you listed has .485 lift which is bigger than most everything Chevy put in any small block. 350 HO cams are close to this lift, I was just wondering how it behaved since most of these larger cams move the torque and HP range further up the rpm range of the engine and seemingly lose some bottom end and vacuum. So my question is, compared to a stock 305 HO roller cam, how much does this cam change the engine characteristics? Judging from the OP's desires for his engine usage he seems to want to maintain the bottom end driveability.
 

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I think what he meant is that all the engines that came with the centerbolt valve covers and the one piece rear main seal were machined to accept a factory roller cam.
 

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Does any one have a complete list of all the sensors needed for this swap? Every web page Ive found has different sensors, and I plan to get an aftermarket harness for it. The main sensor im worried about because im not sure what it is called is located between the spark plug holes for cylinders 1 and 3, it looks like a temperature sensor but there is already 2 temp sensors (cts and its) in the manifold?
First thing is to decide whether you want to go MAF (mass air flow sensor), or MAP (manifold air pressure). Personally, I think MAF is better, but you cannot allow any water in it, so maybe speed density is the way to go for off road.

Next: Painless is the best harness made, but a lot of money can be saved by going with the little guys. Just make sure they include all the circuits you want.

Fuel pump must be capable of providing at least 50 psi at WOT. I recommend the Walbro 255 in tank, or inline, your choice

Sensors:
Oil pressure sensor / This must be used, or the ECM will shut down the injectors.

Knock sensor / This can be programmed out if you wish. I delete in big cam applications, but close to stock it is reasonable to consider keeping it.

Speed sensor / TPI really needs to know whether it is moving or not. Every hillbilly chewing on a matchstick will tell you it can be bypassed. I highly recommend it. See here:
Stealth Conversions Vehicle Speed Sensors for V8 Conversions

CTS (coolant temp sensor) should be located in the front of intake.

MAP (manifold air pressure sensor) / Because you have a MAF intake you can keep this sensor under the dash should you choose.

MAT (manifold air temp sensor) This is identical to the CTS and screws into the bottom of the plenum. Some move it in front of the throttlebody, but I'd leave it there.

O2 / This is the most important, because it allows closed loop operation where the computer maintains 14.7 AFR except at WOT. If it is placed in a header collector I would use the heated version. I get datalogs from guys where it goes open at idle, because it doesn't stay hot enough.

TPS (throttle position sensor) Yours is probably already on there, and is the good adjustable one. It is a rheostat and is subject to failure, and or flat spots so keep an eye on it.

IAC (idle air control) This allows air to bypass the throttleblade at an amount determined by the ECM to maintain proper idle. The throttleblade screw in the throttlebody came from the factory with a plug not to be adjusted. Some think they can adjust idle like a carb, but it is not the case. While it may make a slight difference for a short period of time it will default back to the programmed idle table.

Park Neutral position switch / A complete VSS circuit includes this switch that tells the ECM it is in park, or neutral, and it adds 100 RPM when it is. You may bypass this in my opinion and the VSS will still function. I modified a neutral safety switch in my B&M shifter to make this work.

Decide what you need and make sure your harness comes with what you want. Speed density uses the 1227730 ECM, but you must make sure you get a calibration module from a TPI. Some people are selling 6 cylinder memcals as AUJP and they never run right.

Hope this helps!
 
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