Archaea

Alright guys - I posted this in the TPI section as well, but I'm looking for quick feedback so I wanted to check as much audience as possible. I've heard on several forums this is the place to be to find out info on the TPI/L98 -- even though I'm looking for information concerning a c4 vette.

here's the info from a shop I'm interested in using in Houston Texas called PrecisionEngine.com

www.precisionengine.com

He claims he can build me a 383 strocker for my 1990 TPI L98 vette using my stock aluminum 113' heads(I'd ship them out to him, he'd port them and install a new valve train as described below) He'd then ship me back a complete long block using my heads and his own block with the specs below. It would bolt up to my TPI intake. It would have a 1 year unlimited mile warranty.

He said I could expect about 350HP crank with this setup using my Stock TPI intake. He said the computer would run fine with it and I wouldn't need to change my fuel system. He said this should be a drop in job, and everything should work fine without any other modifications. What do you guys think about this deal?
I looked the shop up in the Better Business Bureau in Houston, he's rated satisfactory.

Looking at the specs below are there any other changes that should be made? Any part swap out recommendations? What do you think of the deal?



SPECIFICATION SHEET


Jonathan,

Thank you for contacting PrecisionEngine.com.

Please review the following quote and specifications to your custom-built 383/350HP SS performance longblock:

 GM 5.7 block bored, honed, decked and align honed
 Durabond cam bearings
 Performance roller camshaft: - (TRW –Speed Pro Camshaft)
o 224/232 @ .050
o .501 lift
o 112 lobe center
 Matching roller lifters and springs
 New sir steel rods 5.7”
 New cast steel 3.75” stroke
 Crankshaft micro-polished less than a 12 ra finish- (Eagle or Adept)
 Speedpro pistons with Molly rings
o 9.2 to 1 compression ratio
 Balanced rotating assembly
 New Melling timing set
 New high volume oil pump
 New gasket set
 New push rods
 New head bolts
 Customer’s aluminum cylinder heads will include the 2.02/1.60 valves
 120 lbs. springs
 3 angle seats
 Bronze guides
 Positive seals
 1.6 roller tip stamped rockers
 Ported intake runners


Total price: $ 2795.00 plus shipping (he said shipping would be about 200 bucks)

So I'd be out $50 or whatever it cost to ship my heads to Houston, then I'd get back in three weeks time a 383 longblock as shown above. I gotta tell you, this price seems good, and the amount of work on my end is comfortable

Sonix

iTrader: (1)

Normally I don't partake in non-third gen threads, but this piqued my interest...

shoulda just kept your mouth shut and said it's for a '90 Camaro, no one woulda called you on it..

I think a 383 with 350 crank HP is not so amazing. I think someone on this very forum used a 350 with ported 113 heads to get a 12.16 timeslip (granted a vastly different combo, but just saying those heads aren't as bad as the rest of the folks on this forum will tell you).

steel rods? hmm, does that fit between forged cast iron (stock style) and forged 4340 ? I'm guessing this is a medium steel style? (anyone have feedback on that?)

are those cast or hyper or forged pistons? I think hypers would work for ya, but just something that you may want to know...

But for only having to supply the heads, and ending up with a 383 built longblock with warantee for $2800, that is a pretty good deal...

xpndbl3

iTrader: (5)

i can typically get a 383 shortblock with .030 over or .060 from a local machine shop for $1200. Then add your heads and a cam and you're done. We're talking cast crank and redone stock rods with ARP bolts....but held up to high 10s for several thousand miles on the street and hundreds of passes, so i'd look elsewhere local.

DENN_SHAH

iTrader: (1)

check you other post on some of the short falls of using a TPI intake & stock chip on that motor.

so you know, its best to not to ask the same question in more than one section here.

Archaea

thanks for the replies, I believe the pistons were going to be chromoly, but since they aren't specified I'd better make sure. If they are cast would it matter much? You think either type would work about the same --- I'd heard cast pistons are good to about 450-500HP. I don't know much about your rod question. XO(TM) Web Site Hosting compression is low enough I was thinking I could add some nitrous later if I feel I want a bit more power, maybe a 75 or 100 shot.

As far as buying the short block. Yeah it would be cheaper, but then I with limited mechanical exp have to be responsible to ensure everything is running and tuned correctly. I'm thinking this is a bit over my head, I can pull the engine and reassemble the heads, connect and disconnect everything, but I don't know much about the rest. The heads and valvetrain would cost another 800-1000, so then your up at $2200 or so. I think saving myself the time and energy and possible frustration involved in chasing all the shops down and purchasing and assebling this thing is worth quite a bit of money. Which with the porting and such he is throwing in- this price seems fair.

As far as posting in each section - Thanks for the notice. I wanted to point out that the responses are are different in each section. Different folk read the different sections so their are two audiences and I'm needing some info in a couple days if possible. I appreciate your patience and advice in the TPI section as well. I'm digesting this stuff as much as I can.

Sonix

iTrader: (1)

your pistons aren't going to be chrome-moly, that's for sure.

cast
hyper
forged
Those are your choices. Cast would probably work for your app, but I would absolutely not ever use nitrous. I think looking at the rest of the motor, hypers is probably what is the implied choice. I'd try and go for that too. 'specially if you were toying with a nitrous shot later.
Heck, i'd decide now if you are toying with nitrous. A 75-100HP shot is not going to require you to rework the whole motor, but i'd make sure no cast pistons, and probably open up the ring gaps a smidge. (Just mention it to the builder, he'll know what to do).
I'd specificy decent rods, and ARP rod bolts. That's generally the failure point - rods and the rod bolts.

Did they mention if the rotating assembly would be balanced? Or how much extra for that? Might be worth considering.

wezeles

sounds like a decent deal for getting a year warranty on the motor as well im sure if hes willing to give you that much warranty on a performance motor hes going to bluprint and balance the thing so he wont have to do it all over again.. but it is kinda a waste of a 383 you could get a but load more power down the road though if you just decide to upgrade heads and cam but your going to atleast have to go with a decent rotating assembly if you wanted to do that...

xpndbl3

iTrader: (5)

for such a small shot it won't matter hypers are good to 150hp typically with no detonation, but FYI cast pistons will take more nitrous than hypers will. A bunch of old timers at the track have been using 250-300 fogger shots on top of cast pistons, cast cranks, and stock rods all done up with ARP bolts. Typically if you're going to spend the money even TRW forged pistons are worth the added safety and expense, but saying cast pistons won't take nitrous isn't true.

Sonix

iTrader: (1)

Well, i'll trust ya I guess, don't have the experience to argue with you, just going by what i've heard.
Hypers are more brittle I guess..

anyway, the ring gaps are one major thing to note for your shortblock, WRT nitrous use. ARP bolts in the bottom end are also good to use.

Archaea

Alright Guys...I actually directed the vendor here and to the other thread I created on the board and asked him to read through this stuff. He got back to me a couple days later and said he didn't agree with everything he read, but that he understood that perhaps he should make the compression higher, and the duration on the cam a bit shorter.

He said he wouldn't want to go to a 10.5.1 compression because he felt that was too high for a troublefree engine and someone (like me) who lacks knowledge required to keep an engine like that running optimally. Which I don't take as an insult. I think the guy is genuinely concerened about my exp. with his product, and wants to make sure I have an engine that is as reliable as it is fun.

The changes he said he was going to make after taking these recommendations into account were:

Change the compression to 10:1.
Use a CS1080R roller cam with a 210/215@50 110 lobe center and 470 lift. He said this cam should better compliment the intake and makes good power from 1500-5000RPM.

He said I could pay 200 extra and get 1.6 roller rockers instead of stamped tip.

He was already going to port the heads for me, but said if I wanted to send him the lower intake he would match port that for me as well for free and if I sent him the upper intake he would be able to maybe minimally help me out there because he said there isn't much to port on the upper intake.

The total price shipped with the roller tip rockers and other changes discussed above was going to be about $3200 shipped.


Do you guys feel these are appropriate changes?

Sonix

iTrader: (1)

Wow, i'm impressed, he came on here and read this.. That's a good guy right there. Going through that trouble just to see what other advice you're getting, and bend his parts/supplies to that - that's damn fine service.

Yea, that's true, his comment on trouble free motoring and 10.5:1 CR.

However, I think that 210-215 is a tad small for a 383. However with the 1.6 roller rockers and the ported lower intake - I think you're still getting a good deal on it. It'll definately pull at low RPM, leave you grinning ear to ear, that's for sure.

xpndbl3

iTrader: (5)

call comp and have them recommend a cam, he just went down like 6 cam sizes there from their cam catalog. Whatever comp chooses is what I would use. A 210/215 cam is barely larger than a stock cam for a 350. That 383 would have tons of lowend but run out of breath quick.

Archaea

Thanks guys - I appreciate the advice...It's all boiling down now.

The vendor called today and left me a voicemail.....he asked me to confirm with him what I wanted my cam specs to be...He has assembled the block and pistons and recieved my heads and has begun porting them...He said he has not put the cam in yet and asked if I had decided change the specs............He said he can still change it to whatever I want it to be should I decide otherwise.

Could anyone describe the difference between the 110 vs. 112 lobe seperation spec?

I called Comp Cams and asked for advice on a cam selection...they pointed me to 08-501-8 which is very close to the one madmax suggested.....The numbers on it are 212,218 with 488 lift on intake and 495 lift on exhaust. Comp Cams said it would normally make power between 1,200 and 5,200 RPM, but on a 383 would make power between about 1,000 and 5,000RPM. He said I should chose 112 lobe seperation because 110 doesn't idle right on a computer controlled car. He said I should put a 58mm throttle body on it and I'd be golden.


There's a side note here....after reading the thread linked below I'm starting to feel like the more torque I can generate out of the engine is probably the route I want to go....The car will be primarily a daily driver.......The TPI intake is probably here to stay...I'm having the vendor port the lower intake out and I'm cleaning up the upper plenium a bit.


http://forums.corvetteforum.com/show....php?t=1534167