JPL3 C5

Hello fellow enthusiasts!
I just wanted to share the progress I've made so far on my 91 Vette top end rebuild. I've been having a blast working on this car but also definitely challenging at times! My goal is to have it up and running by the New Year Here is a list of the mods I've done and are currently doing ;
-Competition Cam Kit #K08-467-8
-XFI280XFI HR13 Hydraulic Roller Camshaft (Lift: .576"/.570" With 1.6 Rockers)
-Comp Cam lifter kit and pushrods
-Hooker Long tube headers
-K&N Filter
-Chrome valve covers
-NGK G Power Platinum spark plugs w/ Accel wires
- TCI Torque converter 242800

More info to come soon with pics!! Thanks for all the good advice! This is a great forum

-Joe

chevyman_ky

Good luck and have fun

JPL3 C5

Thanks! I will have some pics up soon!

Churchkey

Did you change cylinder heads or modify the guides on the stock heads? Stock 113 heads have a guide to retainer interference issue @ +.500 valve opening.
Suggest a valve spring change + check for coil bind.

Luck with your build.

JPL3 C5

Thanks! I didn't change the heads but I did port them. I actually am a little concerned now about interference issues after researching it more. I installed the comp cams Beehive Valve Springs: Top 1.065" O.D., .650" I.D.; Bottom 1.415" O.D., 1.000" I.D. w/ the comp cam retainers.
Do you think I'll be okay with this spring set up? Thanks so much for the heads up! Also here are some pics, please let me know what you think

Churchkey

Valve springs may be ok check clearance between spring coils with a feeler gauge on both intake & exhaust when each valve is fully open. I like .060 minimum clearance.

Aftermarket retainers may clear the stem seals when the valves are full open need to check.

Hard to tell from the pic but the rollers on the rocker arms look to be off center & toward the exhaust valve side of the head. Magic marker an intake & exhaust valve, reassemble, cycle the assembly & check the witness marks on the valve stems.

Have concerns with pic 3 looks like the engine was cycled without the spider plate installed there are lifters installed 90* to the cam centerline = the lifter rollers were scraping the cam lobes instead of rolling over the lobes. Suggest removing the lifters & eyeball the cam lobes they may be damaged. Also check each lifter roller for damage.

JPL3 C5

Got ya. I'll check the clearance with a feeler gage. Pic 3 was taken before I set the lash on the springs, does that make any difference in reference to the degree of the lifters in that pic? Thanks again for your help!

JPL3 C5

Just checked the valve clearance and it was at .090

thurman_merman

This was the first thing I thought too. I had a little more clearance but I know most max around .525. Good thing to double check.

If you want to make good power you will want to look at other intake manifolds. I didn't see any listed in your first post and the tpi is severely rpm limited.

JPL3 C5

I absolutely agree! I didn't have the money in my budget for a whole new intake system so I invested in a grinder and carbide bits and went to town! LOL. I ported the intake manifold and runners but had to buy a used plenum I found already ported on ebay (I butchered the original one trying to port it myself ) Here are some pics

I also measured the springs at .090. Is that okay in your opinion? I appreciate it!!

thurman_merman

They say you want .090 between your valve seal and spring retainer and .060 before coil bind in the springs. You should check both.

I'm no expert but it looks like you have made good headway with your porting. You should see some gain but your runners are a major restriction. You might be able to find a used set of siameased runners to help your cause but I wouldn't spend much on the tpi setup, it's better spent on mini ram or a super ram. Some of the experienced tpi guys will be able to help more in that area, I chunked my tpi setup first thing.

Notice: this has been debated at length on this forum and this is just my opinion, I'm not looking to start an argument on tpi vs the world. (Some guys will want to take it there)

JPL3 C5

Yeah, I've noticed that is a touchy subject after reading alot of posts on this forum. No problem man! I just appreciate the help and advice.

I am about to assemble the TPI system back together and prep the manifold to install. Could anyone give me some advice as to what all I can assemble onto the motor before I hook the lift up to it? FYI, I didn't take the hood off. Thanks!!

GREGGPENN

I mounted mine sans runners. I used bolt-holes on the lower intake to lift/install the motor. With the exception of the water pump, I installed accessories once mounted.

With the cam chosen, I also agree that runners (at a minimum) are called for. Even with nicely ported stock runners, it'll be starving for air. I tend to think runners restrict the most due to their semi-circular shape. Larger runners help to mitigate that somewhat.

As for the choice between individual/siamesed runners, I've noted better results with separate runners.

I like the option of a shorter-runner intake [especially] if it's an automatic....though the tuning changes will be somewhat more extensive.

Pwnage1337

280XFI is going to want a little more RPM than a LTR intake is willing to provide IMO.

JPL3 C5

Thanks for the input! There is another member that pm'd me about a Mini ram system for sale. Just waiting to here back on the price. You don't think I'll have enough even with the porting I did? The only reason I ask is because I worked pretty hard on it.

GREGGPENN

The porting on your runners looks great though it looks like you only radiused the entrances? Basically, since the tubes are 1.45" (throughout) they are inherently too small. If you weren't aware, they were developed for the SBC 305 and "leveraged" for the 350 builds to avoid additional manufacturing costs.

Aftermarket runners are anywhere from 1.6"(SLP, to 1.65" (Edelbrock, Accel, ASM) to 1.9" (FFI). If you look at flow POTENTIAL for the bigger sizes 1.9" is the best. COMPLETELY ported ASM runners (TPIS) can hit 1.75". I can't find (easily) find flow numbers anymore but I mega ported (and siamesed) SLPs for my 383. IIRC, 250cfm was about the best I could shoot for...maybe 260 with the mild siamesing I also did.

113 heads flow something like 195/160 "out-of-the-box". Your porting looks much more thorough on their "runners". If you did a really good job there, they have a 250/190 potential IIRC. IDEALLY, you want your intake to flow 15% MORE than your heads.

I'm just as much an advocate of longtube setups -- if they can be made to flow enough. And, I think you are AT LEAST 1/4" IF NOT 1/2" too small on your intake runner tubes. With the radiused inlets I'm not sure you outflow what the 113s were BEFORE you ported them. When you factor in the "need" for 15% more, there is absolutely no way those runners are big enough.

Realistically, the lower intake runners are also too small...though narrowing as you approach the head isn't all bad. If you had ported/honed LARGE DIAMETER tubed upper/lower intake, I think you'd be a lot happier with a torque build. If you have an automatic, the miniram is definitely going to suit you better.....provided you don't have "mileage" gears.

Of course we said nothing about your rear gear ratio.

GREGGPENN

If it helps, here is an archive of a website whose numbers I used to refer to ALL THE TIME.

Obviously, it was created/meant to tout the HSR but it's helpful to have numbers for various intakes and setups. I didn't verify all the pages/links still work...but the most useful page (to me) is the one I linked above.

Notice what it say about porting of the stock "TPI" in the first paragraph. Many of us think the TPI Shootout article provides great info as well. Even an extrude-honed "stock" TPI doesn't fare very well compared to large-tube, siamesed, etc...

If you don't know what extrude-honed means, you should....to help you understand the shootout article. Also this one.

JPL3 C5

Hey there and thanks for all the great information! I looked at those links and they are very informative. I'm kinda bummed though about my lower intake not being ported enough, but my skills are kind of limited in that area since it was my 1st time. I'm trying to come up with the money to buy the Minram from another member. In the meantime the build continues and now I have to come up with a way to clean my engine compartment while the car is in my garage on jack stands!! That should be interesting! lol

GREGGPENN

I didn't notice if your motor is out, but I had to do the same. I threw down plastic/cardboard/whatever...and went to town. Stood IN THE ENGINE BAY and cleaned everything I could reach. Used a rattle-can to freshen up a few places too. (The plastic is to catch drippings/debris so you don't have to lie in a cesspool during reinstallation.)

Didn't really take THAT long either. Just need a couple good wire soft-bristle brushes and a bucket/bottle of degreaser. And, a few rags of course. Some use simple green. I think I used something in a purple jug....more of an industrial degreaser.

TA

I did the same