Hi, the '91 Formula (LB9) i bought in January has VALVE&RING damage...taking the opportunity to upgrade and go bigger. Not very experienced but with ALL the research i've done the L31-R Vortec seems to be the "least" difficult route to go (I kno it aint gonna be easy) I could use some help on the Springs and Cam: I have read both that the stock is OK and that the springs needs to be changed (LS6) and the cam should be upgraded from the stock Truck too ? (to take advantage of TPI I plan on running.) I have $3600 so, I am prolly ready to make the purchases and get it done. Any clarifications and suggestions are greatly appreciated? (i've gone thru Sticky/Threads)

Also, best place to source 91-92 350 Chip? (hoping to find somewhere that already has the BIN for the L31r, +injectors, Vats delete, EGR(?)...?)

 

A brand new GM L31 long block would be a good option. The stock L31 cam and springs are matched and will work fine together and will run well with the TPI setup. You don't NEED to swap the cam. A stock L31 with TPI will run very similarly to a stock L98. If you do swap the cam, then yes, you will need to swap the springs. However, your $3,600 budget doesn't allow for a cam swap, and is a bit light overall. The price of the GM L31 long block is $3K, plus the $400 SDPC Vortec TPI intake you will need and that's your budget right there. You will still need injectors, a chip, gaskets, tune-up parts and other miscellaneous stuff. There are remanufactured L31 long blocks out there for around $2K, but those are a crapshoot.

 

Oh wow, that price has gone up quite markedly? I purchased my brand new GM crate L31R from Jegs in 2018 (deflating it was that long ago and I still haven't fitted it) for 1,899 USD!

 

Yeah, it used to be an unbeatable deal for a brand new 350. Not sure what happened and why, but the price went up $1,000 last year or maybe the year before. It's still not a bad price at $3K, but not the great deal it was.

 

They were built in Mexico years ago. Had one in my Express van that was bought from a local GM dealer in 2006. TOTAL JUNK. The vortec heads flowed poorly and cracked easily, the lifters were junk, roller wheels locked up munching on the cam and to add insult to injury the #1 crank throw was not round which ended up wearing #1 rod bearing prematurely. Replaced it with a 383 I built from the block up. Plan to revisit that 350 someday soon and build it from the block up with aftermarket aluminum heads.

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https://www.jegs.com/i/JEGS/059/0282/10002/-1#

 

What relevance does it being made in Mexico have to your otherwise useful consumer feedback?

 

Because it was built in a cut rate method there and quality control was obviously lacking alot. The new version is built in the USA. The best engines were Canadian though and many of the Vortec heads that went down the assembly line in production GM vehicles were also cast and built in Canada. The Canadian heads are higher flowing.

 

Well, I have been seriously overwhelmed with getting together a "parts-list" and making a decision. The more I read and research the L31-R Vortec the more I am wondering if I should wait and BUY a brand new 350/357 or L31-R from GMPP(the price actually rose across the board on the L31-R Vortec in the last week about $200 more bucks from the major vendors to $3200 NEW-) The reviews I have read and concerns I have tried to get to the bottom of arent convincing. I had been leaning torwards JEGS reman from ATK apparently, and although I am sure the negative is given often than the positive, its still makes me wonder if its just not a safe gamble. I tried to call Jegs and ATK to see if the valve height and lift could be double checked before shipping to me because I have read among other problems , that there is no guarantee on uniformity between different engines or even within the same meeting Original specs. I got the expected answer "materials and procedures are the highest quality and precision..."=Blanket Statement. So, maybe I am over thinkin this BUT $4K (actually total is like $4800-5400 for parts, FIRST intake, and header/exhaust) is ALOT of cash for Me. So idk if I should risk spending $2200 on a reman engine. I can prolly get a REMAN with efi for 4k turnkey. smh idk any suggestions or advice is welcomed seriously strugglin...