Why did Summit tell me I needed a LT1 throttle body to fit on my Holley Stealth Ram? Why can't I use the stock L98 throttle body? Plus, will upgrading to a 58mm throttle body be beneficial when I install the HSR? Already have 350, XE 268 cam, roller rockers, headers, ported heads..

 

hey iceman what you can do is look for Doug Flynn on this board he works at Holley I am sure he can point you in the right direction

 

well summit is wrong on that account. i just put my TPI 48mm TB on my HSR yesterday. i have a holley 52mm TB also. i'll be dynoing it with the 48mm and then swap to the 52mm.

www.fl-thirdgen.org/mrr23/mrr23-11.html

 

the STOCK L98 throttle body will bolt right on a HOLLEY STEALTH RAM,
the engine your useing the HSR on will determine the CFM needs of the engine,
as a basic rule the STANDARD L98 THROTTLE BODY will work just fine on engines below about 350-400 hp, the stock throttle body flows about 600-670cfm
and youll not NEED to go to a 58mm throttle body until youve done extensive mods to the engine

heres a couple calculators,

http://www.newcovenant.com/speedcraf.../intakecfm.htm

http://users.erols.com/srweiss/calcafhp.htm

http://users.erols.com/srweiss/calccarb.htm

 

I figured that was the case (Holley probably just recommends the larger LT1 TB), but it appears Summit is giving courtesy calls out before they ship the HSR. They said Holley advertised it as a direct bolt on replacement (although because of you guys, I knew better) and must be getting many returns and complaints. I was intrigued when they told me about the throttle body. Mrr23, I will be interested in those dynos with the two throttle bodies. And since I won't be exceeding 350 hp, I won't worry too much about it... I just came across a 58mm at a pretty good price.....maybe if I stroke it to a 383...hmmmmm

 

MY stock 89 T-body didnt fit the cable guide hit the fuel rail.I had to grind the bottom off the cable guide.If you go to http://www.hotrodlane.cc/ look under online tech and What throttle body do you have? You can see there are six different T-body designs.

 

My BBK 52mm (for 87 TPI) bolted right on with zero problems.

 

I had to grind my stock TB also. it hit the rail as well. it is a TB off a 91 z28.

 

www.stealthram.com i have purchased this domain just for us people. give me links to your webpages and i'll put it up. email is mrrjjdh03@aol.com

 

Sweet! Maybe you can con Holley into paying for the site!

 

Just an FYI... this pic clearly shows that the stealth ram has the necessary IAC hole to use the 85-88 style throttle body.

 

Hey! That looks just like mine! Looks a bit better on top of an engine block though, rather than on my bedroom floor for me to stare at..... and trip over. Anyway, I assume you are talking about that single hole front and center. When I did my engine swap, I didn't separate the TB from the plenum, so I didn't know what that was. Jim, are you using the serpentine setup or the v-belt style? With the old style, there is a bracket that mounts on the front of the intake driver's side, but it looks like it will fit perfectly. I had to build that bracket cause the factory one wouldn't fit on my current Accel intake base.


Did any of you guys polish the inside of the intake runners..... mine looks like a litte rough (grainy) casting and looks like it would be worth the time to do so.

 

I port matched mine & smoothed the runners with 220 grit sandpaper. You don't need to polish the intake ports, just take off any casting flaws that impede airflow.

 

I'm not running a stealth ram. I nabbed that pic off mrr23's site just to show the IAC hole. It's fairly safe to say that since the new and old TBs bolt up the same, that as long as the IAC hole is there, an old style TB will work fine.

 

port matching helps as does pollishing up the internal runner surfaces slightly but what helps flow some is rounding off the corners on the port entrances of that center (+)area seperating the runners, just stay away from the outer port wall/gasket seal surfaces, look closely thru the throttle blade openings and youll see that (+) that has flat upper edges that cam be beveled/rounded to assist airflow into the runner entances