What's up, guys and gals?

Long time, no post. I used to have the screen name 1996man on this forum but it has been several years ago and I can no longer get access to that old email so I created a new screen name so hopefully I can start interacting with this great community again.

Let me see if I can get all the facts out there. I own a 1996 LT4 coupe that unfortunately has been sitting for years. I am now finally at a point where I can start to restore it and I would like some help with my planning of this build. I wish I could go all out but budget is still a minor concern here. I had a LT4 Hotcam from many years ago that I never got around to installing before. It is brand new, still wrapped up with oil and should still be 100% useable so I would like to base the build around that. I also really want to use the scorpion 1.7 rockers. I have read a lot about the Hotcam/1.7 rocker combo and I have decided that this is the route that I would like to go.

I am trying to go with a pretty mild but tried and true proven build but I still have a couple questions and I am hoping all you freindly experienced people can help me put together a list of part numbers that I will need for this project.

I will list the part numbers I have so far and hopefully you can help me figure out what else I need in order to do this job correctly.

As mentioned before, I am going with the LT4 hotcam PN#24502586
I am also going to go with the Scorpion 1.7 Rockers #1026 these use the 7/16 studs which I am told is what the LT4 uses from the factory.
Speaking of studs, am I reading this correctly that these 7/16 studs are smart to replace with ARP hardware? If so, what ARP part number would I need for these?
Any other ARP hardware that would be good to use? I hear nothing but good things about them so depending on what the cost difference is, I wouldn't mind getting them where needed.
As far as the valve springs go for this project, I am told by many people that the Comp Cams Springs PN#26918 will handle the combined lift of the LT4 Hotcam and 1.7 rockers.
After doing a lot of research, a lot of people are recommending the LS7 lifters #12499225.

Another question I have is pushrods. I know there are several guys running standard pushrod length with the 1.7 rockers and LT4hotcam but I am told that even using the LS7 lifters will affect the pushrod length needed. Does anybody know exactly what length I would need with this combo or how I would even do the math to figure that out? Are hardened pushrods nessecary for a 400-430HP build? If so, thats fine but what brand should I go with? Does ARP make these as well or is it better to go with another brand? ANy part numbers would be greatly appreciated.

I am told by many people that going with the somewhat expensive LT4 Extreme duty timing set PN#12370835 is a very plug and play option and should hold all the power I have planned

I know from reading several build threads on different forums over the years that the SVO #30 injectors used to be popular for this type of build. Would these be enough for this build and power level?
I went to go find part numbers on those but was finding several different numbers. Are these still the best route to go? What is the current part number that you would suggest?

Is PCM4Less still the best place to get a mail order tune for this build? What do those usually run?

I think I will start a seperate thread about the optispark. Too many variables to discuss here

I have not seen much mentioned about the balancer in these build threads. Any suggestions on what to go with here?

I had an electric waterpump on this car before it went down. I think it was a Meizer? Do they still make products for the LT1/4?

Is there any need to do a fuel pressure regulator with this build or would that all be taken care of with the mail order tune?

I am going to start a seperate thread about some gasket questions I have

I dont' want to spend a ton of money sending my heads out to AI or LE because I dont' really think they need that much more flow for the valvetrain that I have planned but if I have to have a local machine shop shave them for instance, would it be possible for them to do valve seals and I still get to keep my lighter sodium filled valves that came on my LT4 heads from the factory?

I think thats all the questions I have for now but I will probably think of more. Once I crack open the old motor and have a better idea of what I am dealing with, I will probably start a new build thread.

Thanks so much in advance! I am really looking forward to this project and hope you guys can help me figure it out.

 

A lot of questions
PCM is a reprogrammed no replaceable chip. It's also obd2. It's possible to back date to obd1, but emissions testing if required is a problem. Stock PCM will work with hot cam without tuning. IDK with 1.7 rockers.
1.7 rocker will require taller valve covers. You also want to besure they will work with center bolt valve covers. Non self aligning rockers will require hardened push rods and guide plates. With 1.7 you will need different springs, "bee hive" type are less likely to bind. You will want machine shop to varify springs don't bind and the retainer won't contact guide at full lift.
Factory LT4 uses unique 10 mm stud and rocker with 8 mm nut. They could be sold as a package to recoup some cash. All the pieces are discontinued so selling or losing just one piece is a problem.
LS roller lifters will fit, however there is information there can be oiling problem. It varies by block, depending on where lifter oil galley was drilled. So better to stick with SBC lifter.
Good Luck

 

Yeah, I know the 96 OBDII doesnt have a burnable chip. But PCM4Less used to be the goto company for 96 vetts. When I just looked at their site, they didnt have anything listed about those year vettes so I wasnt sure.

The LT4s had larger valvecovers than teh LT1s so lots of people have been able to have the 1.7s fit without too much problem.
I may even end up going with larger valve covers anyway for cosmetic reasons.

I understand the hotcam paired with the 1.7 rockers will be too much for LT4 springs.
That is why I listed I was going to be using the 918 Comp Cams beehive springs.

 

Are you rebuilding the engine or just getting it running again? If it's the latter I wouldn't add a hotcam and 1.7 rockers on a engine that has been sitting for years. You're increasing the valve train stress for a few extra HP. I'd do the basics i.e. compression test fuel pressure blah blah before purchasing performance parts

 

Yeah, the engine will be going down to the block either way.

Super old rings, bearing, ect that need to be replaced.....

 

Excellent. This is one of the classic 'while you're in there' scenarios. There's a post for discounted super damper for sale on this subforum you might want to check out. I think it's a direct fit, no shim needed for LT4.

 

Manley Trend etc make decent pushrods by all means upgrade

 

I'm using Bosch 35# EV14 injectors with my hotcam and I'm at 82% duty cycle at 6200 rpm's with 12.4 AFR. I like the Deatschwerks injectors because they come with full documentation.

 

I did an LT4 "Hotcam" swap with the engine in the car and the heads on the engine.

First off, the LT4 hotcam kit was designed as a drop in for...you guessed it...an LT4.
To heep it simple, use 1.6 rockers, same as the stock LT4 rockers.

get a new set of oem springs to match the LT4 hotcam, these are one of the FEW bargains for these engines; when I last looked they were $40 plus change for a new oem set.

The LT4 hotcam with 1.6 rockers makes 0.525 inch lift, the LT4 Hotcam springs handle a max lift of...you guessed it...0.525 inch.

The LT4 uses a one year only pedestal mounted self aligning 1.6 roller rockers. In my experience, the "ears" on the rocker which keep the rocker aligned on the top of the valve stem, just aren't quite big enough to do the job...so THE ONE THING I'd change would be to ditch the pedestal mounts and self aligning rockers (which by the way, are only available oem, and if available at all, are going to be ridiculously expensive) and install aftermarket studs, roller rockers, guide plates and hardened pushrods.

When I changed out the valve springs, I also changed out the valve seals. This is one place it pays to go oem; most aftermarket valve seals are the same, both intake and exhaust. The oem seals use the standard (i.e common) seal on the intake, but use a special higher temperature material, red in color, on the exhaust valves. A small detail, but worth it.

The oem LT4 timing chain is a single roller chain; the LT4 "extreme duty" chain is also a single roller, but much larger...or as I like to say, "it looks like something that came out of a sawmill", robust, but expensive.

If your running an electric water pump, there any of a number of aftermarket double roller chains that will work.

I would be definitely change out the oem oil pump stub drive in the lifter valley. Goggle LT engine "oil pump drive failures" and you'll see why.

With the oil pan off, roll in a new set of main and rod bearings, a new oil pump and that's about it.

My own Hotcam swap into my 96 LT4 coupe also involved changing out to old (leaking) multitek fuel injectors with Bosch III injectors in the 22 to 24 lb range (same as oem) from FIC; ran perfect, sailed through California smog, and used the stock PCM without any issues.

Good luck.

 

^^ Do they still ask the OEM oil pump drive?

seems all I can find is a $150 billet piece from Tick.

 

Well that's a bitch. I run a billet piece. I'm sure that sooner or later a "new" piece shows up on ebay. As noted the billet piece is bare. You need an old piece to strip down for the internals and here's (yet another rub), the drive gear, while the EXTERNAL gear dimensions are the same as any other distributor drive gear on any other chevy small block, the LT specific drive gear uses a smaller diameter drive shaft and other drive gears DO NOT interchange. THANKFULLY, new LT specific drive gears are now available (they weren't a few years ago). So the choice is, hold onto your wallet, $150 for a billet housing, old shaft from oem piece, plus $50 for a new gear. Or keep watching ebay. Good luck.

P.S another example of the "general" fixing something that didn't need to be fixed.

 

Wow that blows..I’m building up a new (stock) motor and was planning to reuse the OEM drive...this has me thinking though...

back to the OP, I ran an LT4 hotcam for years in my LT1 and it will be going back in my new motor. Lots of good advise in this thread.

 

So is the billet oil pump drive gear not a good piece? Don't mean to go off topic. But yes, good advice has been given.

 

First of all, why the factory buried the oil pump stub drive in the lifter valley is beyond me. But I digress,

Yes the billet piece is a definite upgrade. Where my project went south was that, at the time (some years ago), the (LT specific) drive gear for the stub drive was not available as a separate piece (they are now) and I reused the drive gear from my original (oem) stub drive...eventually this gear failed.

I probably wouldn't have had any problem there either, except this LT4 engine had ongoing low oil pressure issues, which I attempted to address with larger volume oil pumps and increasingly heavier oil....think back to the olden times when 50 weight was considered "racing oil". Long story short, the oil pressure issues were eventually traced to the middle cam bearing in the block...or more accurately, to the middle cam bearing WHICH WAS NEVER INSTALLED AT THE FACTORY. No cam bearing = not much oil pressure. Go figure.

 

Thanks for all the input guys!
I think I may hold off on the 1.7 rockers for now.
Still havent got the old motor pulled yet but hopefully sometime next week I will have a little bit better idea of what I have to work with.
I will post updates when I have them

Thanks again!