D_Smith87

I have looked everywhere on my engine and cannot find where it says 5.0 or 5.7, the guy i bought the car from told me it's a 305, but the catalyst sticker on the under side of the hood says 5.7 and the VIN on that matches the VIN inside my car, so now i just need to find where on the engine it says 5.0 or 5.7, it would help if someone could show me a pic.

87IROC-DAN61

Hello D_Smith87!!

Look at the pad on the engine block, on the passenger side front, under your alternator, or A/C compressor if you have A/C, it should contain a code ie 1HXXXXXX, "X" being the last 6 digits of your vin, also it should have an engine suffix code ie "SFU", and also a date code ie VXXXX, "X" being the month and day of your engine being assembled.

The catalyst sticker doesn't contain the vehicle vin in Canada, but it may in the US, however there is usually a code like "ZUL" then under that is the engine size 5.0 liter, or 5.7 liter whichever the case may be. Underneath that is another code which may contain 5.7 within it, but that doesn't prove your engine to be a 5.7, as this catalyst system can be used on both 5.0/5.7 engines.

I would post pictures, but I haven't figured out how to do that yet!!

You should be able to figure it out given the above info!!

Let me know what you find!!



Just another bit of info, vin related, your vin should be pretty close to: 1G1FP21??H?XXXXXX the first ? in the example is the "engine code" and could be F= 5.0L or 8 = 5.7L the second ? is a "check digit" and it can be 0-9, and the third ? is the "plant of assembly", and it could be N = Norwood Ohio, or L= Los Angeles.

If you have a 5.0 (305) with the automatic, your HP is 190, 5.0 (305) with the 5 speed manual, your HP is 215, and if you have the 5.7 (350) your HP is 220, all this is of course factory specs!!

vetteoz

iTrader: (13)

Twin_Turbo

iTrader: (25)

It will say 5.0 or 5.7 behind the drivers side head, under the wiper motor.

Like mentioned above, check the vin for the 8 and check the rpo codes for L98 listing.

87IROC-DAN61

Hello vetteoz!!

Thanks for the picture, I knew someone would post one!!

If I could only learn how to do it........

87IROC-DAN61

Hello Twin_Turbo!!

Thanks for adding that, on my first attempt to post a reply, I had that in there, but I left it out, and concentrated on the engine pad, that really will give it away as to what he has!!

yamban

Heres the code on the back of my 1987 350 TPI



I have not seen the code with my eyes, I just searched around with my hands then after a few minutes managed a picture.

Twin_Turbo

iTrader: (25)

You can see it here:



It's from an 87 L98 too, should be identical to yours

87IROC-DAN61

Hello yamban!!

I was wondering if you or anybody knew why the "G" was after the 5.7L in the picture?

Could it be there to denote that it is a "gas" motor as opposed to a "diesel"?

87WS6

iTrader: (1)

Not sure. My Vortec truck block (5.7L) says the same thing on it.

yamban

I'm not positive but I think it means litre gallon

Twin_Turbo

iTrader: (25)

I think it has to do with the fact that it's a roller block, combined with the SGI. All non roller earlier blocks just say 5.7L without the G. May stand for Generation .. who knows

PV9685

I may be wrong but if you look up from below the engine on the driver's side of the block there will be a 3-digit numeric code that tells which block you are running. I can't remember what mine was but it checked out as a 305. I battled to see the rear pad and jammed my head against the firewall to check the pad.. the pad said 5.0L so, I think it is easier to just look up from below in some cases.

D_Smith87

turns out the easiest way is to open up a valve cover and check head casting 081= 305 tpi heads, but that engine is toast onto the world of 4 inch bore!

PV9685

Eh, you never know what someone swapped out in the last 20 years, especially since we are seeing less and less of these cars because people constantly tried their best to destroy them. Turns out both pads behind both pads identify the block. The DR side has 5.0L or 5.7L cast in large print and the pass side has the block type ID that will tell CI and 2/4bolt and a year range and application. Oddly the numbers on the front of the block tell you nothing... kinda stupid of them. The trick I just realized that I never thought of 5 years back is to simply aim a digital camera or cellphone camera into that crevice and you'll know what you've got as soon as you pull away.

Chevy86 IROC-Z

iTrader: (17)

That is thee worst way to figure out the type of engine. Not everyone rebuilds engines properly. I have seen a few 350 engines that have 305 heads.

Chevy86 IROC-Z

iTrader: (17)

Or you can get a telescopic mirror and struggle to get the right angle and read out the numbers to someone. Keep in mind about my method though that the numbers will come out backwards. Best bet will be to use PV9685's method and get a camera. You may need to move around some wirelooms and such but it's probably the best method.

PhoenixFirebird

iTrader: (2)

Ruined I assume?

081 heads on a 350 are just asking for detonation

Chevy86 IROC-Z

iTrader: (17)

Excactly. Higher compression and higher risk of det.

jacksonml3

Does a 305 and 350 tpi share the same face value? I just bought a 88 trans am, they guy I bought it from said that it has the vette motor in it. Its there a such thing as a vette 305. I've seen pics of the 350 tpi, and I swear that is looks the same as what is under my hood? My vin's 8th symbol denotes 'f.'

86WS6

iTrader: (1)

If your vin says F, it was built as a 305. It may not have the OE engine though.

jacksonml3

Thank you... What is the oe engine? Is that better or worst than the other 305, or are they the same? Will the modifications that I found for a 350 work on a 305? Is it just better, wiser, cheaper to swap out for the 5.7?
The mods were:
Two vortec cylinder heads
Intake manifold
Bolt set
Gaskets, plugs, button, cap
A little help in the right direction is what I need. I'd like to know where should I go from here. I love this car, its like a dream car. I have other stuff that my peers love, but this is the car that I love the most. I do not want to merely keep her running, I want to open her up when I feel like it too.

86WS6

iTrader: (1)

F code means 305 TPI. OE is original equipment. Someone may have changed the engine though, and it may not be the original engine for your car.

PV9685

Many people simply refer to the L98-derived motors as the same motor as the Vette. The main difference though was that the L98 Vette 350 had Aluminum heads.. But, no matter the case the whole top end from the heads-up is poorly designed - unless you like having a truck motor in your car

If you are on a budget you will be very pleased by keeping the 305 block in your car - so long as it is in decent shape. I have aftermarket Vortec heads, 1.6 roller rockers (with stock 88/89 cam; which is a GREAT stock cam! Bear in mind that to use 1.6 rockers on Vortecs you should drill the wholes that the pushrods pass through in the heads out to 1/2"!), Weiand Single plane intake manifold (everything just barely fits under the hood), inexpensive Headman full-length headers/all2.5" exhaust w/H-pipe and dual thrush muffs, and a Holly 600cfm 4 barrel(don't over carb!).

I am very pleased with my setup and while it would be nice to have a 350 - gas prices are insane; you could tell people this thing is a 383 and they'd believe it in a heartbeat - this thing is like a raped-ape dude; when you do the budget mods to a smaller cubic inch motor you get a higher-performing motor with less output. What I mean is that if you take your cam and put it in a 350 it is like going to a smaller cam, all of the "small" parts are "bigger" on a smaller-displacement engine. So, using the 305 you will have a more cost effective time getting more output per cubic inch. The more output you get per cubic inch, the more insane your motor will seem - even though it may not make as much power as a larger one. For a street driven car I would not concern myself with higher displacement - the 305 has plenty for these cars unless you really want the extra....

Oh and to answer your question - all of the 350 stuff fits the same except the pistons, piston rings, and when you get heads you can't really fit like 2.02/1.6 valves but 1.94/1.6 is fine. Everything else if I recall properly is identical.

bestracing

Just an FYI, the rear of the block tag only works for later year motors. I have two 350 blocks from the late 60's and early 70's and they do not have "5.7L" casted on the rear bell housing mounting flange.

Really a nice dual plane manifold is better for most street applications especially the 305. Long runners help build torque at lower RPMs. I've seen test build preform better with the Edelbrock RPM Air-Gap than a single plane manifold. I have a 305 with stock heads, RPM Air-Gap, Holley 570, Crane .454/.480 lift 218/220@0.050 dur and have run a best of 14.74 in the quarter. I pulled a 2.21 60' due to I still have the factory stall and 2.73 gears out back.

I've built race motors including a 388 and that is where you will see the best application of a single plane manifold.

The 2.02/1.6 will fit it's not recommended because the cylinder walls will shroud the valves and they won't flow properly.

afremont

As a general rule of thumb, I would just say that for the street, if you have a clutch use a single plane. If you have an automatic, use a dual plane. With a clutch you launch at any RPM you choose, with an automatic it's pretty much up to the transmission. A dual plane helps you build more power at lower RPMs because the air velocity is higher and atomization is better in the smaller plenum. Throttle response will also be better for the very same reasons.

bestracing

You can launch an automatic the same way with a good stall converter. Done it for 11 years with a 67 Camaro with a 5500 stall and transbrake. Launch RPM was 3.5K to 4K depending on track condition and motor we were running.

Still with a manual once the clutch is fully out your RPM's will drop to what ever the power-train demands which is dependent on your forward speed and gear combination.

jacksonml3

Thank you so much for the information. I just want to be in an informed position, not spend too much cash, and have this bird flying.

D_Smith87

Yes after having the heads off it is a 305 block, found a motor out of a 73 truck 2 bolt main block, went through that and rebuilt it (factory dish pistons) so had the 081 (305) heads crack checked and jet washed and milled to 51cc to put me right under 10-1, then i spent many many hours porting and polishing them, making the bowls into an actual bowl shape, and doing mad work with a carbide tip to get that tiny exhaust port to a respectable size, then after that i had the guy at machine shop set the heads up since ive heard lots of horror stories about incorrectly shimming a stock head for a cam in the .500 lift range, plus it came free with the competition valve job, springs were matched to the cam that came out of a "blueprint 383 405 horse 440 tq motor" assembled everything together, ran 13 heat cycles on the motor thus far and still tuning the carb in and idle and such, everything works great and no detonation problems on 93 octane, did a 20% mix 110 octane when i put fresher gas in it, excited to see what kinda power numbers i can put down with those done up tpi heads, kept the 1.84 valves since its a street motor and im looking for a real tight low end. im guessing hp and torque numbers around 370hp and 405tq, whats your guy's imput on those numbers?

D_Smith87

oh yeah also the cam specs are .487/508, 234/244 duration at .050 and a 112 degree lobe sep.

Johnny Blaze

iTrader: (15)

What did the chambers CC out too after you reshaped them?

Johnny Blaze

iTrader: (15)

What intake are you running? Thats a lot of duration!

D_Smith87

The machinist cc'd them after he reshaped them, took i believe 32 thousanths off to make em 51cc, and yeh its a fair amount of duration but with 112 lsa, it has very good street manners, and i wanted as much duration i could get under 6k rpms, ive seen too many times people building ticking time bomb of motors, the motors peak hp is at like 5500 which i will set it at, unless i take it to the strip ill give it 5700 rpm, going to get one of those dial adjustable ignition boxes. my motors about at the peak of what i feel comfortable with a stock bottom end and its a 2 bolt main motor, but the clearances were great when i was assembling it, giving it a gentle break in and gonna be just fine, couldnt zero in on my compression ratio cuz i couldnt find the head gasket specs, stock so around .040, but the bore size i could not find guessing 4.100 which most are, i know its safe because my exhaust duration will allow a high C.R being 244 @ .050, any input is much appreciated thanks guys.

D_Smith87

and intake im running a edelbrock performer eps, idle-5500 rpm rating, its a street motor so im looking for low end grunt and driveability, maybe take it to the strip once a year if im lucky, built it to compare to my buddy with a 73 olds 442 with a 70s 455 rated 370hp and like 515 torque with a muncie m-22 4 speed, but he has like 2.78 gears vs. my 3.42s and weighs much more than me, my car has alot of weight reduction done to it, ripped out anything having to do with the factory computer, heaters, everything uneccesary, doesnt even have a radio. ud be really suprised how much all the extra weight the factory tpi stuff has in it, that air pump itself was a boat anchor hanging off the motor.