mxnoah418

My trans am developed a pretty noticeable tapping noise at 127k after running it pretty hard one day. Does GM or anyone make a direct replacement for it? Or any crate engine that will work fine with my tpi setup?

mmadden55

https://www.summitracing.com/search/...rate%20Engines

mxnoah418

That link brought up 10+ pages of engines.... hoping to narrow it down a bit to something you guys have used before.

TTOP350

iTrader: (8)

I have used a few 96ish 350 truck short blocks that I got new from GM.
Pretty darn cheap (1200ish) and you have to reuse a LOT of your other parts but worth it for a mild driver..

mmadden55

the l31 r is the best deal and best engine however it has vortec heads.

Tuned Performance

iTrader: (92)

The l31 is a good engine but you need to buy a tpi vortec base

https://sdparts.com/i-23896057-sdpc-...SABEgKtA_D_BwE

Tuned Performance

iTrader: (92)

If you want to tune your tpi or datalog for someone a l31 with a hot cam works well.
You need to have the heads machined for the higher lift and Alex springs or beehive ls work good too.

mxnoah418

So if I would buy a l31 and a vortec base, everything else would bolt up and be good? Stock tune on the care would be fine?

Tuned Performance

iTrader: (92)

Every thing will bolt up both engines your 89 and a l31 are a one piece rear main seal.
It doesn’t have to be tuned but you can gain more performance if it is.
Since your car has a l98 and t5 it would be a custom tune.

mxnoah418

Gotcha, best place to buy a l31? Does gm sell them directly? Does the car need to be on a dyno to be tuned or is there someone on the internet that has tunes?

Tuned Performance

iTrader: (92)

https://www.summitracing.com/parts/nal-12530283
You would need to datalog here is a device that hooks to your ecm and laptop.
Dyno tuning works or sending a datalog to a tuner using tuner pro rt.
http://www.moates.net/aldu1-and-cabl1-p-127.html
There are multiple sources for tunes , I do them , Scott Hansen, ed write of fast chips or brian Harris tbi chips .com

mxnoah418

Awesome, I'll definitely hook up with you when I get to that point.

Tuned Performance

iTrader: (92)

The l31 comes with a roller cam but you could always swap it out for a. Teter cam before it’s installed. The t5 is your weakness.

mxnoah418

Well I definitely dont want to up the hp to more than the t5 can take. We just swapped the auto out for that.

Dyno Don

iTrader: (7)

If you want the simplest way to go...
Use this short block remachine your heads reuse your cam, a Cloyes 9-3145 timing set and no tuning required. Bolt it all together with the rest of your engine parts and go.

https://www.ebay.com/p/Chevrolet-Per...ne/22003366217

All the specs

https://paceperformance.com/i-238406...ck-engine.html

mxnoah418

Hmm. Not sure if I would want to reuse my cam with 127k on it.. I got some rough numbers from 2 engine builders near me and it was more $ just to do the machining than what it was for a complete crate engine...

Abubaca

iTrader: (3)

Don, why would you have to machine the heads? ...or are you suggesting that simply as a refresh? I looked it over real quick...maybe I missed something. -But...that IS a quality looking piece from GM.

mmadden55

bone stock with the tpi the l31 should be 40 to 60 hp stouter than the original engine.

Galaxie500XL

iTrader: (1)

This is the exact thing I'm doing to my '88...figure on around 400 foot pounds of torque, and other than the Scoggin-Dickey manifold, it will look bone stock.


I'd recommend this swap wholeheartedly...but would start shopping for a T56.


I'm having one rebuilt now to install in my car, hopefully, I'll have the T56 done in a couple of months.

NowhereFast

Gonna be putting a ZZ4 short block in my car (the one in that link), I put AFR 180s on it, but it is a very nice piece with good parts in it. I trust factory built engines more than the aftermarket rebuilders or even local guys. Maybe I'm wrong to think that way, but I've heard a lot of horror stories.

mxnoah418

Just to clarify, your going with the l31?

Drew

iTrader: (58)

What advantage does the ZZ short block have over the L31R? Just looking at the published specs on the ZZ, it's not exactly impressive. Last I checked it's a nodular iron crank, powdered metal rods, and hypereutectic pistons. Is that much different from the 4-bolt main Vortec truck engine? Because the Vortec L31R adds a roller cam with all the extras, Vortec heads, all the tins, oil pump, blah blah blah. Plus the L31R crate engine is reportedly all new parts, and $200-300 less than the ZZ short block. Am I missing something or is L31R about $1,000 more engine for the money? Even if a person pulled the Vortec heads, and truck cam, it would seem like a better deal.


https://www.jegs.com/i/Chevrolet-Per...30283/10002/-1

Dyno Don

iTrader: (7)

Why not? it is steel from the factory.

Yes, just refresh, valve job, seals, resurface etc.

Drew

Read it again, 4bolt block, steel crank.

The L31 has a old cam technology (small), linkbelt timing chain (that gets sloppy after a few miles) dished pistons. ZZ motors have flat tops.

If you're going to do it, might as well make it better, maybe a better cam too, but that gets back to having to tune.

[quote] Even if a person pulled the Vortec heads, and truck cam, it would seem like a better deal.[/qoute]

I Agree but then, back to tuning.

Drew

iTrader: (58)

Yeah, I'm seeing that in the online descriptions. The GMPP catalog around here somewhere is more ambiguous. It shows two different crankshafts for the ZZ4, and LT4. Some pages say the ZZ4 uses a forged steel crank, others say nodular iron. Could be a running change I suppose, or a misprint in the catalog.

9.8:1 compression ratio on the ZZ vs 9.4:1 on the Vortec. It'd be nice to know the part number for the pistons GM uses in the L31R, but they seem a bit tight lipped about the internals.

Not sure how much difference it'd make under TPI.

mxnoah418

If I would rebuild the 350 I have, I'd like to put a new cam in it. Just a mild lobe. Nothing too crazy. What would you guys suggest?

Drew

iTrader: (58)

Spend a butt-load at your local machine shop having the heads reconditioned, and machined for more lift. Because if you don't, nearly any "performance" cam is going to bounce the retainers off the valve seals. Or you know, leave the cam alone because you don't want to dump money into the stock heads, and you'd have to tune for it anyway...

mxnoah418

I think I am going to go with the sp350/357 crate engine. Get the vortec intake adapter so I can still use my tpi. And then tune the ecm accordingly. Obviously it will be alittle more power than the stock 350 I have. So the t5 wc will be alittle overpowered. I'll just be easy on it and upgrade to a t56 later if needed.

burnout88

ATK, makes a nice drop in TPI crate motor. Comes with Edelbrock 60cc aluminum heads, roller cam and no tuning for $3,900. The cam is very close to stock specs.

https://www.high-performance-engines...tte-p/hp57.htm

Horsepower: 289
Torque: 370 lb/ft
Block: Seasoned OE 4 Bolt Main 1pc Seal Roller Block P/S Dipstick
Bore/Stroke: 4.040 x 3.480
Year Range: 1987-1991
Displacement: 350 C.I.D.
Crankshaft: OE Cast Crank 3.480" Stroke Externally Balanced Rear/Internal Front 1pc.
Connecting Rods: OE Powder Metal 5.700" Stock Bolts
Pistons: Hypereutectic Dished
Piston Rings: Moly Rings
Compression Ratio: 10.0:1 Compression
Camshaft: Hydraulic Roller
Camshaft Specifications: 207/214 @050 .411in/.428ex 117LSA
Camshaft Bearings: Installed & Clocked to OEM Position
Cylinder Heads: Edelbrock Performer Aluminum 60cc/165cc 2.02/1.60
Freeze Plugs: Brass Installed & Sealed
Rocker Arms: Stamped Steel 1.6 Ratio
Oil Galley Plugs: Installed & Sealed
Oil Pan: OE 5qt.
Weight:350

mxnoah418

Wow, that is a sweet setup! You may have just changed my mind...

burnout88

These are the heads that come on it part #60879
http://www.edelbrock.com/automotive/...rbolt-sb.shtml

It does have the vette TPI heads so you will either have to use a vette tpi intake base or any Edelbrock or Accel intake base (they are drilled for both).

mxnoah418

So the TPI base that I have for mine won't work? That sucks...

burnout88

Correct, but you can find a used stock TPI vette intake base very cheap. Especially over on the vette forums. Probably get one for $50

Ty92Z

iTrader: (11)

Your base will work fine, you just need to elongate the 4 center bolt holes.

mxnoah418

Gotcha, thanks for the info!

Fast355

iTrader: (2)

The newest ZZx engines no longer have forged cranks. They have nodular iron cranks. It was a running change sometime early in the ZZ4 production. The nodular crank is the same one that is in the 1-ton 4-bolt main 350 Vortec. The 1-ton Vortec engine also uses the same roller timing set as the ZZ4. As for the SPO 357 HP 350 crate mentioned above. It would be thousands of dollars cheaper to buy a 1-ton 350 Vortec, swap the cam to the SPO cam and swap the plastic timing cover to the GM cover made without provision for the crank sensor and end up with the very same engine. You could duplicate the SPO 357 HP 350 for $2500 with new GM parts, FWIW. The Vortec does have dished pistions, but you could also pull the factory 0.051" compressed head gasket off that crate engine, substitute the .028" thick GM performance parts one they should have built those engines with while you swap the heads to LS6 valve springs on Comp 787 retainers. I think the SPO cam would run better with the beehives than the OEM vortec springs they equipped those engines with. I would also upgrade to 1.6:1 full roller rockers at the same time. For those while you have the heads off, drill the pushrod holes to 1/2". For less than $3,000 you could do all of the above and have a valvetrain that was stable to 6,500 rpm.

I am speaking from first hand experience with the SPO 357 HP cam in a 4-bolt main 350 Vortec. Mine was running with 0.020" milled 906 vortecs with 2.02/1.60 valves and 1.6:1 full roller rockers. The SPO cam is pretty tame at only 215/223 @ .050 but has a nice choppy idle with its 108* LSA and 1* retarded 109 ICL. It had a great powerband under a L31 marine intake manifold with Tri-Y headers. I ran it in my Express van with a 4L85E and 4.56 geared 10.5" 14-bolt and put down more than 300 RWHP with it.

Abubaca

iTrader: (3)

Buy GM.
Buy Local.
Pay top dollar and buy from a national performance engine builder.

Those would by my only 3 options. ....I'd stay away from any national budget builder.

burnout88

That will work also but I have always found the vette intakes for super cheap and found it a cleaner install with less hassle. I have a couple in my garage right now and one I got for $25.00.

mxnoah418

I did some research on ATK. Found alot of bad reviews stating that they are outsourcing alot and quality has really gone down. Also very poor customer service. So I guess I'm back to the sp350 or having a local guy rebuild it.

kaos420

check out blueprint engines regardless of what others say on here I know PLENTY of guys even myself that run there engines from budget builds to crazy 396 engines they built an never had a problem.great prices an awesome customer service..

Abubaca

iTrader: (3)

I think too many have had negative experiences for BP to be considered an option. Of course....I'm not the consumer in this instance.

indy82z

iTrader: (5)

Still looks like the L31-R is still the best bargain to me. Heck, Jegs has it for $170 off right now. https://www.jegs.com/i/Chevrolet-Per...30283/10002/-1

GTA1990

iTrader: (1)

agreed. I've pulled the trigger on this and will likely slap a pro flo XT edelbrock intake on it. I think this will be way ahead of a comparable TPI setup bhp/$$$

goodnight

Galaxie500XL

iTrader: (1)

Compression and bottom end appear to be in good shape in my L98, so for now, I'm just buying new Vortec heads. Occasionally, they're on sale from GM Performance for about $600.00 a pair. I already have the Scoggin-Dickey Vortec TPI manifold, so I'm going the cheaper route first, but later, when the L98 gets tired, I'll go with a new L31.

Abubaca

iTrader: (3)

Make sure to document that if ya don't mind. Not a lot of info on that intake.

tillyvick14

Sorry to ask a potentially stupid question. I have a 91 Formula with the L98 engine. The L98 has a crack in the block. I am looking at the L31 as a replacement engine along with the SD3816 TPI Base Intake Baseplate so that I can use my existing factory TPI setup. Is that all that is required to swap in an L31? Does the SD3816 simply bolt up as an adapter or are there some other modifications that are going to be required? Thank you very much for all your help. I'm trying to explain to my mechanic what needs to be done for this swap so I can get my Formula back on the road.

TTOP350

iTrader: (8)

Vortec long block, vortec tpi intake base and it'll drop right in.. I would have the intake ported though.

Tuned Performance

iTrader: (92)

tillyvick14

Thank you all! Went ahead and ordered an L31 and the vortec tpi base, hopefully my mechanic can figure out everything else with dropping it in without too much problem!

GTA1990

iTrader: (1)

sure. I have the intake (7138), a LS1 TB (with adaptor) together with the LT4 Hotcam, LS6 springs and associated comp-cam retainers.

The install will likely be Q1 2019 but will def. take it to the dyno once its on its feed tune wise; figure I'll get one run in before the T5 goes purgatory...

Out-Cast

iTrader: (1)

Can anyone tell me what the HP of this L31 Engine is? I have been debating building my stock 350 L98 but for the price of these motors its kind of a no brainer to buy a new drop in Engine.
I am looking for 330-350HP out of an Engine. Or can you reccommend a different motor as I am thinking this L31 only produces 255ish for HP ??
I drive the Car every day from Spring to Fall and need it to be reliable, but worth the money spent in regards to performance.
And I am wanting to bolt on my Stock TPI System. So can someone tell me EXACTLY what I need to accomplish that and will my Hedman Headers bolt onto this Engine?
Thanks