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iTrader: (1)

Hey guys so I decided to buy a new Crate engine for my IROC. Currently running a 5.7 TPI. 1st off I want to verify this Engine bolts into our 3rd gens without modifications? Wondering if you guys can direct me in what I need to change or purchase. I will be purchasing a SD Intake to keep my TPI system. I will be installing a new water pump as well, not sure of the proper part number?
https://www.jegs.com/i/Chevrolet-Per...10007/10002/-1
1st-Will my current Hedman headers bolt up to the new Engine?
2nd-Do I need a new distributor?
3rd- I am running a mini starter so will that fit or need a new one?
4th-What Harmonic balancer will I need?
5th: What flywheel and flexplate will I need?
6th-Does the oil pan on this Engine clear the underside for the 3rd gen?

Anything else you guys can think of?

I do not trust anyone around here to help me with this list so much appreciate your help in getting this completely setup, ready to go. I am looking at doing it Mid August. I work away from home and want to make sure I have everything ready to go and take a few days to get it done.

dmccain

iTrader: (2)

Save yourself a ton of $ by buying an L31-R and swapping a cam and upgrading the springs with an Alex Spring kit. You wont be much over 2k doing this and you will have a roller cam engine with as much power.

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iTrader: (1)

I have looked at the L31 Engines and they only come with what 250 HP ? I really do not want to get into tearing apart a brand new Engine to install a Cam and maybe Heads? I don't think the L31 R comes with Vortec Heads does it? Or is there a difference between the L31 and L31 R ?
The engine I listed comes with Vortec heads and 333Hp. So am I right in thinking that by the time I change out the Heads and Cam on the L31, I would be on par with the 350 Engine I listed?

dmccain

iTrader: (2)

The L31 is rated at 255HP on a stock truck with a crappy fuel injection setup, lame duck cam, and computer restrictions. With a simple cam swap these engines easily go over 300HP. As long as you don't go over 450-460 lift on your cam you probably even would be ok with stock springs.You will have to ge a different intake and maybe some tuning but with your stock L98 cam in an L31 with headers id say you would pickup 50+hp easy.

dmccain

iTrader: (2)

If I'm not mistaken this HO motor is a flat tappet Vortec head engine. L31-R is a rebuilt roller cam Vortec engine. The L-31-R is a better deal IMO and can make same power a lot cheaper.

dmccain

iTrader: (2)

Friend of mine had an old 350 HO. It was the Corvette 113 aluminum heads and a little more than stock cam. Ran good did 13.5 1/4 trips in his S10. Long story short he blew it up, dropped in a Vortec 350 with a stock L98 cam I gave him and headers..it went 12.7s or 12.9s I cant remember exactly but it was considerably faster!

mikeceli

iTrader: (2)

Just listening.

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iTrader: (1)

So this is the L31 you are referring to, the 1st one on this page at $1600?
Its not giving me a description as to what heads are on it from the Factory, any input on that?
So what Cam would you put in this motor?
Keep in mind this is a daily driven car, no strip use and don’t need it to have a lobe like a drag car engine.
Thanks.
https://www.jegs.com/i/JEGS/059/0282/10002/-1

dmccain

iTrader: (2)

Yep Vortec heads, L31 is a Vortec engine. Id use my stock L98 cam or a GM94666492 cam: 214int 220exh 452 465 lift. This cam would be on the bubble with stock springs and probably no noticeable idle at all but definitely a lil boost in power. I should put one of these in my L98 but I'm sticking with my stock cam because like you i wont be racing just cruising. The stock L98 you have has a considerable better cam than what the stock L31 comes with.

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iTrader: (1)

Man thanks for the info.
So by installing the cam you suggested, what do you think the HP rating would be overall?
255 stock + ? By adding the Cam?

I will look up the cost of that Cam right now.
I will call the shop tomorrow where I was ordering the 350 Base engine from and get a price on the L31.
if I can be at 300HP for $1000 less then sounds like a win win.
The only additional cost would be getting someone to install the Cam.and I would also upgrade the springs as you suggested. I have never done one before. Are they difficult to install? I rebuild snowmobile engines during the Winter and am mechanically inclined.
ill be tearing out my Stock motor myself.

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iTrader: (1)

So I did a little bit of Math on the costs vs each motor.
L31 Engine $1602

New Cam $230
Labor $300
Spring kit $100??
Total $2250ish
Possible 305HP


350 Base motor $3116. Savings of $866ish
Stock 333HP.

WildCard600

A "proper" L31 would be the GM manufactured one @~$2k https://www.jegs.com/i/Chevrolet-Per...81432/10002/-1

The one you linked, "Jegs" brand is a re-manufactured ATK special. I would read some reviews on ATK before putting my money anywhere near one of their products.

FWIW

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iTrader: (1)

Ahh ok. Well thanks for that clarification. I was wondering what engine on that page would be the better/proper one. Then I see the “R” in the one you posted the link for.


Its looking like it will be the original Base 350 Engine I listed.
Now I need to figure out all the parts I need as listed in my original post.

WildCard600

I would spend a few more bucks for a roller block personally

https://www.jegs.com/i/Chevrolet-Per...67080/10002/-1

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iTrader: (1)

What’s the advantage of this engine over the original one I posted?
I would still be able to install my TPI System on this engine correct? I know that’s a yes but need to be 100% certain there’s no hidden surprises.
Thanks

WildCard600

Flat tappet vs Roller. You could hardly give me a flat tappet engine.

http://www.superchevy.com/how-to/pro...for-your-chevy

Mortorq

This cam (12677151)comes stock with Chevy’s SP350/357 somewhat recent crate motor.
Seems to use the stock L31 Vortec head springs as well.
Lots of good reviews on this cam if you check around.
Tight 108 LSA with not an excessive amount of duration @ .050” to cause big overlap problems.

sofakingdom

iTrader: (1)

Your TPI will NOT fit onto any motor with Vortec heads. The issue is MUCH deeper than "bolt hole angle". Here's what it looks like.



You will need the $$$Vortec TPI base$$$, and TPI itself (the long runners) will largely nullify all benefits that you might otherwise get from those heads. Furthermore it will not be emissions-compliant, if that's a thing in your area, without a bunch more $$$$ on EGR work-arounds. Another option could possibly be an aftermarket intake such as a Stealth Ram but that can cause other issues such as hood fitment and throttle cables; and of course, still leaves you emissions non-compliant.

I would NOT buy a motor with a flat-tappet cam in it under ANY circumstances for a situation like yours. That ENTIRELY leaves out the motor you first posted about. Drop that one from consideration.

Stock Vortec heads come with arguably THE WORST valve springs EVAH. No matter what cam you go with, they will be inadequate. They are arguably inadequate for the stock weenie Vortec cam which is … weenie.

The marinized version from GM is better and might work out OK as-is, even with TPI on top of it, with its somewhat better cam and whatever all else they did to it. No matter what though, if you use a motor with Vortec heads, you will HAVE TO deal with what I spoke of in the 1st paragraph.

And of course no matter what you do, it will need TUNING.

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iTrader: (1)

WELLL FAAAACK.... So I was looking at this Engine last night as well. Cant I buy a Scoggin Dickies Intake and bolt my TPI System onto this Engine or the one I originally listed? Links attached.
https://www.summitracing.com/int/parts/nal-19367080
https://sdparts.com/i-23896057-sdpc-...baseplate.html

dmccain

iTrader: (2)

I love the Vortec engines but for what you are doing I would just rebuild your current engine with a wee bit more cam if I didn't go with the Vortec. The L98 is a great engine and is what I'm going with myself.

sofakingdom

iTrader: (1)

Yes that is the $$$baseplate$$$ I was referring to.

A whole Stealth Ram costs very little more and is probably good for 75 more HP on almost any motor. (almost...) On that one, for sure.

midias

That 350 is flat tappet you dont want it. Go L31 get a decent cam over 300 NP with alex spring kit you can go near 400HP. It will idle better and run smoother with the roller cam.

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iTrader: (1)

Thanks for all the Info guys. Stressing out here its a tough decision.
So if I go with the better engine that was posted, can I add a Scoggin Dickies intake and my TPI system and be fine?
I was also looking at this one and am I right thinking I don’t need an aftermarket intake and can bolt my TPI system
on and the rest of my components?
https://www.jegs.com/i/Chevrolet-Per...55658/10002/-1

midias

Let me make it very easy for you do not buy a motor with a flat tappet cam only roller. I would rebuild my factory l98 for performance before I would by either of the two motors are listed. For something in the low 300 you should be able to get away with the factory TPI manifold but you will need to get new injectors and tune the motor.

WildCard600

Flat tappet. Avoid.

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iTrader: (1)

Guys Thanks for your patience and responses.
To save $$, would it be reasonable to go with the 350/290 motor in this link and add a Roller Cam? If so what roller Cam would be sufficient?
this engine is rated at 300+ HP and a Cam would add what 25-30HP ?
And this would also save me from buying an Intake to use my TPI System right?
https://www.summitracing.com/parts/nal-19355658/

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iTrader: (1)

I am waiting for a callback from a guy that was recommended to me. If the cost of rebuilding is the same as a new crate engine I will go with the Crate Engine.

WildCard600

It's more than just adding a roller cam, there are additional valve train parts that are needed as well. That will drive costs up.

Plus that engine has a 2 piece rear main seal which will require a different flexplate/flywheel than your '87 uses (assuming orginal '87 engine).

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iTrader: (1)

Damn it I can’t win here
Well back to the 350/357 motor and SD Intake.

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iTrader: (1)

here’s the prices I got on the Engines.
Reminder that I am in Canada so prices are different then the USA and the Summitt websites.
350/290 Engine 308HP $4090 Flat Tappet Cam
350 Base Engine 333HP $4186 Flat Tappet Cam
350/357 Engine 357HP $5028 Roller Cam

So looking at these it’s either the 350/290 and swap out the Cam, and I don’t need to buy an intake correct? Since it’s got Iron heads I can just bolt on my TPI components?
And will my Distributor, Flywheel etc bolts onto this engine?
Warranty is void if I add a Cam.

Or just go all in and get the 350/357 Engine. That’s a bank account killer especially since I have to purchase the intake as well.

dmccain

iTrader: (2)

L31-R

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iTrader: (1)

I know I know lol
So would that be one of these 2 engines? They bolt have the Roller cam. It says Iron heads then in the description it says Vortec heads. What am I missing here ? And if it’s vortec heads ill
have to buy an intake for my TPI. But this option is waaaaay cheaper.

https://www.summitracing.com/search?...te%20engine%20

WildCard600

Iron Vortec heads, as opposed to aluminum Vortec heads. You will need the vortec TPI intake you posted earlier.

The main difference in the two engines in your link is that one is 2 bolt mains and the more expensive is 4 bolt mains.

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iTrader: (1)

Prices for those 2 Engines I got are:
https://www.summitracing.com/parts/nal-12681432/ is $3997
Engine ending in 1431 is $4195
They dont list the HP numbers for these engines though. Are they at 255 was it?

WildCard600

The L31 replacement engines are rated at 255 IIRC, assuming reusing the original exhaust, intake and fuel injection that the original application had. You may be higher (or lower) depending.

GeneralDisorder

iTrader: (1)

Performance, Reliability, Value.

Pick Two.

Personally - I would find a good used Vortec (~$200 - maybe less), do a reseal - possibly new rings (NO HONING!!!) on it along with camshaft and suitable drop-in valve springs.

Spend the bulk of the money on a First Performance intake with Vortec or dual bolt pattern ($1000), nice fat injectors, and an ESL box.

Used Vortec motors are CHEAP. And it's pretty easy to find good ones. Invest in a filter cutter and check the filter before buying.

GD

sofakingdom

iTrader: (1)

It is meaningless to buy based on advertised HP "numbers" if you plan to change the cam and use TPI.

Those "numbers" are based on running the long block AS IS, and a Holley (NOT Edelbrock) 4-bbl carb and long-tube headers. You will NOT approach them with TPI; not even close. As an example, the old ZZ4 was "rated" at 345 HP; the IDENTICAL SAME long block except with a different cam, and TPI, was "rated" at, what, 250 HP or something, as the Vette L98.

Pay NO attention to those; instead, concentrate on the pistons & heads(compression), heads (flow and intake bolt pattern), and valve train system (presence of roller apparatus).

Focus on what will translate to your build, and ignore the parts you will either throw in the trash and change (cam), or that an assumption is made (Holley carb for example) that doesn't apply to your intentions.

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iTrader: (1)

Well back to the over thinking my engine choice. Been a crazy hot weekend at the Camp Ground playing around on the seadoos!
Choices are the L31 R, Base 350-333HP, and the 350/357 Engine. If I decide to go with the 333HP base engine with tappet Cam, I will replace the cam when the warranty is up,
And I get it about the advertised HP and not getting that with my TPI system. But I have to use it as a base for $ value and reference to what the potential of each Engine is. I just think its a better choice to go with the 333hp Base Engine then the L31 R since there's such a big difference in the HP #s posted ??

So regardless of what Engine I choose, Do I have to worry about the degree of separation between the lobes on the Cam in these Engines? This is in regards to keeping my TPI System.

midias

Good luck hope the computer tunes with the tappet cam and nothing goes flat. Hope your initial tune is good enough for the first 20 minute break in.

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iTrader: (1)

Ok so are you saying with the tappet cam I’ll need tuning like right away, and with the roller cam I will not need tuning?
Im guessing I’ll need tuning regardless but with a tappet cam it’s definately a bad running engine right from startup?

midias

Flat tappet cams require a very specific break in to properly mate the cam to the lifters or it can go flat and die early. Also special oil. Roller does not

WildCard600

What he is saying is that initial startup with a flat tappet cam is critical, otherwise you can damage the cam. If your car isn't running correctly and able to perform the initial start up/break in you WILL wipe out your cam. Reason #2323129814 to avoid a flat tappet cam.

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iTrader: (1)

Ok Perfect thanks for that info. Good to know. So the L31 R has a roller cam and compression ratio of 9:4:1, 333HP Base has a tappet cam and is 9:0:1. On a Car Engine is this difference in Compression going to show much performance difference?
Help me understand why I go with a rated 250 HP Engine over a 333hp rated engine? This is assuming that when I bolt on my TPI system, I will loose X or same amount of HP on each engine. The thing here is the price difference for me is only $100. Would it be better to go with the 333HP with tappet Cam and change to a roller Cam right away and I will end up with a significant amount of higher HP right from the install?

midias

The L31 is rated with factory truck equipment, manifolds and cats the other is with headers and performance intake manifold and tuned carb. Other differences come from cam profile.

Here is a sample procedure but do what you want. I just like roller because they make more power idle better get more mpg and last longer

1. Install the Camshaft.
2. Set the Valve Lash or Preload as recommended by the manufacturer.
3. Prime the Oiling System.
4. Set the Initial Ignition Timing.
5. For carbureted engines, make sure fuel bowls are full and any air is bled from the fuel lines.
6. Start the engine and immediately raise rpm to 3,000.
7. Vary rpm between 1,500 and 3,000 for the next 20-30 minutes.
   1. Use a slow, steady acceleration/deceleration pattern.
8. Shut down the engine and let it cool.
9. Drain the oil and change the oil filter.
   1. This removes any metal particles from the break-in process.
10. Refill the engine with a petroleum-based oil and zinc additive.

The initial break-in is now complete. After the next 500 miles of normal driving, change the oil and oil filter again.

• If you choose a synthetic oil, we recommend putting about 5,000 miles on the camshaft with petroleum-based oil before switching.

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iTrader: (1)

The more I read about the L31 I am liking it.
I would just hate to be disappointed after the install with the performance.
Our 350 Engines are rated at 240HP, so I view it as almost no gain. I know my engine is not producing 240hp with 90,000 miles on it, but how much better would a new 250hp engine be is my concern.
I have Hedman headers on my current engine that would definitely go on the L31.

midias

Read this. L31 can make plenty of power. But buy what you want

https://www.performancetrucks.net/fo...ded-dd-514343/

dmccain

iTrader: (2)

Trust us. That L31 will make WAY more power than your L98 with the same cam and TPI setup. Even with its baby cam the L31 will make more power. The intake will set you back a little but I'm sure it would be a better deal than every other crate engine you have looked at. If I didn't go this route I'd just rebuild the L98, a few bolt-ons really wakes them up man.

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iTrader: (1)

Ya I am having trouble Finding someone within 5 hours to rebuild
My engine. And from my little bit of research, the Labour cost would be around $2000-$2500.
Whats a rebuild kit worth for the L98 Engines? I’m thinking pistons, rings, rods all gaskets etc.
would there be any machining work required?

mikeceli

iTrader: (2)

If you need to get your vehicle SMOG tested, the L31 wont work, due to no provisions for EGR (Exhaust Gas Recirculation). YES, there are ways to rig-up an EGR pickup, but that too will likely fail the test/visual inspection. I am NOT familer w/ Canada's SMOG laws.

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iTrader: (1)

No smog tests required: