hey,

I'm thinking about putting in a 'different than stock' cam when I do the rebuild (which will be soon).

It's an 89 350 TBI, non-roller, for now I'll keep the stock manifolds and heads. I obviously want torque at or near idle and up to about 4500 at least. I realize the stock cam would be near perfect, but was wondering if I could go one step up.
I hear staying at 112* LSA is best, but I'm not sure if these 111" (one was recommended directly by Comp, but they said it was 112, there spec card says 111) cams will be Ok.

Here are four that I am considering (all Comp) duration is at .050:

PN 12-304-4, 201/206, 406/406, 111

PN 12-388-4, 206/212, 425/440, 112

PN 12-249-4, 206/212, 434/444, 112

PN 12-231-2, 206/214, 432/453, 111

Stock (I hear) is about:

194/203, 395/415, unsure on LSA

Comparing 12-388-4 vs. 12-249-4, for example, would more lift with same duration be better for the lower end?

All the Comp cams are rated at 1000-5000 rpm, except for 12-304-4 which is idle to 4700.

Concensus seems to be that the duration and lift of all of these will be fine with the stock chip, not sure about that LSA tough.

Tranny/tcase will be NV4500 (w/ 6.34 first) and EB D20 (2.46) with 4.88s and 38s for wheeling, 35s street/winter. This will be primarily a crawler, with some street duty


Your thoughts?

thanks,

Charly

I'd stick with stock since there will not be any issues with the setup. I'm sure the TBI motor will have plenty of low end torque.

Any ideas when they went with roller lifters on the TBI motor?

Charles

I've heard that blocks started coming with the machine work and the mounts for the roller lifter retaining assembly in 88 or so (in trucks), but mine does not have any of this and it is definitely an 89.

The lighter the rig the less trouble you would have with a big cam. What ya driving?

YJ...... it will have a 14 Bolt FF by the end of the summer and someday (most likely) a 60 front (44 for now).

I used the 12-338-4. No noticeable idle lope, good low end still, and makes good power from 2000 up. Everything else stock, except bored .030. I like the cam. OBTW, no codes on the computer, runs clean. Keep the duration in control with the larger lobe seperation and the stock chip wont mind

2000 seems a little high for me....I know the 'cruising range' of cams with the low 200 durations (according to Comp) is supposed to start at around 2400 or so....maybe those will be a little high for me. Maybe stock will be a better idea.

I assure you, that cam has noooooo problem with low end torque.

Charly, In my opinion, with any of those cams you will not see a real( I mean wow I am really glad I shelled out a hundred and somethin bucks) difference. TBI makes decent low end grunt in stock form and in that Yj you should have plenty of Torque..Had the stock TBI in a Fj40 before the M715 Had it with both auto and manual 14 bolt rear 10 bolt front(sucked had plenty of torque to snap those axles)....

Hows the project going???Have not heard much out of you over the other way????If it gets too bad remember to not hold your breath and count to 10...:D :D :D

Kaiserman,

Project is going well. Just dropped the block off at the machine shop, it will need to be bored .030.

I'm buying one of the master kits from either Speed-O-Motive, Northern or Powerhouse.

I'm deciding on the cam, because a couple of these places offer cam upgrades(even Comp's) for not much extra (vs, the stock replacement cam that comes in the kit). So I really only need to add on about half of the cost of the better cam, since I'm already paying for the replacement cam in the kit.

I'm going with hypereutectic pistons, moly rings (keeping stock CR).

Cruise rpm at 65 in OD (NV4500) will be about 2100-2200 for me.

The stock YJ GVW is 4300 lbs. With the 14 bolt, 44, 350, tranny, rockers and corners......and gear of course, it'll be a little heavier.

I have had good luck with Northern stuff in the past..Their prices are great too..
The other board is down I guess...Dont know any more than that.You???
Good luck on the project...If it gets too close to crunch time and you need some wrenchin buddies I could probably round up myself and Dan and 1 or 2 more to come help...Let me know...

I guess they tried to upgrade it and ended up fawkin it up somehow.

And thanks for the offer, I'll let you know.

I just finished my tbi rebuild. .030, the comp cam, hyperuetectic, hv pump(put a stock spring in it), resized the rods, felpro kit, stock CR, new scat crank, dr chain. Bought it all from Northern, got a great price on the parts, and the kit was nice.

Keith,

wow.....I'm doing just about the same thing... (no need for a crank though)

Couple questions though:

What's the deal with the hv pump with a stock spring? advantage?

And I hear lift = torque, as far as cams go...so with the same duration and a little more lift (same LSA too), what do you think of the 12-249-4 I have listed?

It's good to hear first hand knowledge on the 12-388-4, are you using a stock GM chip?...

Thanks,

Charly

As far as the cam, I dont think the larger lift would hurt you. I do know that the the LSA and duration is the biggest worry with the computer. And yes, I am using the stock chip. I am using a 92 comp, prom is AWLC. I chose a 92 because in Cali with a manual, 92's did not have air injection. I chose the HV pump because when I lug it in low range, I wanted the added flow at the low rpm. No need for a 70lb spring in it though, dont need that much pressure. So, I put the stock spring in the pump, that came with it. That way, it makes a bit more pressure at low rmp, and is able to bypass at higher R's. Pressure on the highway is around 35-40. TBI motor idles around 650, and a stock pump, according to my machinist is and unbelievable 6psi at 1000 rmp. I had a hard time believing that, but he showed it to me in the manual. At 1000rmp, mine runs at least 35.

Who is offering the 12-388-4 with their kit? When I ordered my kit from Northern, I chose the stock cam. Then after a few days of him-hawin', I decided to buy the 388.

I needed a new crank, and a .030 bore. The hyperuetectic pistons use a tight clearance. I had mine set up for .0015", but You could even go to .001. The moly rings that came in the kit did not need any gapping, but make sure to check em all.

Good luck

Originally posted by Keith
So, I put the stock spring in the pump, that came with it.

Who is offering the 12-388-4 with their kit?

Ok, just to clarify (I'm tired....lol) you got the stock spring from where?

And Speed-O-Motive specifically... was happy to offer a Comp cam upgrade in their kit, for the cost of the balance....they use FMs for the stock cams.

the pump I got was a Melling, it came with both springs.

Charley, how much was the kit from SoM?

Off the top of my head, it was about $450 with shipping.

I still need to ask what the other companies will do that for.

Here is what I got

Hyper pistons
speed pro stock cam
double roller chain
felpro gaskets
hv pump
fm lifters
hasting moly rings
clevite 77 main and rod bearings
fm cam bearings
HD pump shaft
brass freeze plugs

that kit cost me $340 from Northern Auto Parts. If I had chose the hotter cam, it would have been $60 more.

I ordered:

FM Hyper pistons (stock CR)
Hastings moly rings
Comp cam (same 12-388-4)
Speed Pro Lifters
Clevite 77 bearings
Cloyes HD DR timing set
Melling HV pump
HD Pump Shaft
Brass freeze plugs
FM cam bearings (already have set of DurBonds though)
Victor Reinz Gaskets (decided I'd stick with these)
Speed Pro upgrade springs
Comp pushrods
cam lube

Shipped for $472 from Northern.

Thanks for all the help.

Charly

Well, I got everything in less than a week (which is impressive, when you live in Maine) and it all looks great....I brought the pistons and my rods w/pistons to the machine shop....

He was quite surprised that they were dished pistons.

Every reference I have says that a VIN K 350 will have 9.4:1 stock compression......he said it can't be with the heads I have.

I finally was able to get a certain answer on my head cc volume....76 cc. With this volume and the dished pistons that are listed for stock replacements..I would have only 8:1 compression.

So I ordered flat tops, which should put me around 8.7 or so.

I'm hoping that with the CR increase and the cam that I should have some decent power above stock......and this is obviously within the limitations of the stock chip, heads, and manifolds (for now).

But I guess anything will be better than the 2.5L that's in there now.

That is a nice kit, and the price sounds pretty good too. I have a 92, and I think the stock CR is 8.5. But I may be wrong. I know that with the stock CP pistons, I still have plenty of power. Make sure the machinist sets up the pistons with minimal clearance of .001. You rings will love you for it. The hasting rings should all be gapped, you should only have to check them. Good luck, let us know how it turns out.

Well, it's in, and runs great.

I ended up rebuilding a D300 (twin sticked it too) at the last minute and am now running that 355TBI, 4500.....Chevy full width mini spooled 44 front, 14 bolt rear with Detroit, hummer wheels and the older hummer 36" GY tires.

The engine runs great, plenty of power, the only issue currently is I have a rolling idle in closed loop, no codes though (using a stock 5.7 auto chip...not sure how much of an issue the memcal could be causing, if any, since it is a 7747 from a 4.3).

Had a code before I hooked up the VSS, and for those wondering, the decel "smoothness" alone is worth using a VSS.

The cam is fine, power is there when I need it, definitely no complaints.

Rebuilding the 355 was fun, and interesting, found out I needed a new crank (all journals miked fine, that's why I decided I can reuse it with STD bearings, but it was the endplay that ended up being excessive...fawker:D ), got a 10/10 reground due to time considerations. After getting the thing in the YJ, all hooked up, ran the cam break in, and noticed that six out of the eight new brass freeze plugs were leaking (yes, including the two rears) and the water pump rear gasket leaked (it was a cheap, but new, pump so we thought it might have been faulty). So, out came the engine, new plugs and sealant, new pump, put the engine back in, started..ran....seemed fine until the thermostat opened and then....drip drip....FAWKER !!

Turns out the 22 lb. radiator cap that Howe recommended was too much pressure, it blew out some plugs and the water pump gasket again.

I still have that cap, and am still taking ideas on how to torture it.

The Howe now cools beautifully with a stock 16 lb. cap.

The Painless harness was easy to install and works fine, no complaints there either.

Ran center dump stock GM manifolds, which a 72 P'up and a C60 gladly gave up, to 2.5" exhaust with a delta flow Flowmaster 40. I like the sound.

Keith , thanks for your help.