Out of curiosity, how big is the stock throttle body, is it 48mm? And is this enough for a charged, stock, 305 TPI (92Z-5 speed)? Thanks

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92 Z-28
305 -5speed
160 thermo.
K&N Air Filters
B&M Ripper
14.7 @ 96mph

 

More air=more power. The more you can flow the better your car will react to the Supercharger. Just remember you will need more fuel for the more air. Custom Prom all the way with a charger and injectors and the other such stuff. I have a 58mm TB on a 355 w/ slp cam and 305 heads. Woke my car up when I put it on.

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86 Trans Am 355 TPI Rebuilt 700R4 with Corvette servo, modified valve body, and a B&M Torque Converter (2000 rpm stall w/ lock up), 87 350 block bored .30 with new crank. Reworked 305 heads with 3-angle valve job. Added in the rebuild was an SLP TPI cam, BBK 58mm Throttle Body,MSD 6A, Hypertech Power Coil, 1.5 Crane roller tipped rocker arms, SLP Intake Runners and Port matching in upper intake including fully ported plenum, TPIS adjustable fuel pressure regulator @ 46psi, Hooker shorty style headers w/ Thermotech heat wrapping, Custom 3” exhaust with Flowmaster muffler and chrome quad tips, Hypertech Thermomaster Computer chip, K&N open element cone filter on modified MAF per TPIS specs, MSD Wires, removal of A/C hardware and added a 1LE firewall cover installed. Also there has been a PST front suspension kit with Hotchkis strut tower brace added. Soon to have Intrax lowering springs.
http://geocities.com/SunsetStrip/Garage/9548/kyle.html

Kills:
95 Talon TSI, 96 Probe GT, 91 T/A L98, 89 RS, 86 Mustang GT, 88 Mustang LX 5.0, 92 Thunderbird V8. couple or ricers that I think were Civics or Preludes not sure what year, 95 Celica GT-S, 94 Chevy 1/4 ton 350, one of those NASCAR F150's

The Third Gen Will Never be Forgotten

 

question for ya why did u use 305 heads?

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Originating member of the SJNEP Crew
Rice..It's whats for dinner!
All new projects put on hold till its fixed..whenever that is
Check out MyGTA
***AOL IM RiceEatinGTA***
Tony

 

He used 305 heads to raise his compression. The 305 heads have 58cc chambers and the cast iron L98 heads have 64cc

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91 Formula
305 TPI 5speed
1LE/G92/WS6

Paxton SN92 polished kit, SLP airfoil, ported/polished plenum, March pulleys, Crane AFPR(43psi),Crane Gold 1.6rrs,MSD coil,MSD6AL,MSD boost-master,Holley 9mm wires,Ac delco R43ts plugs,custom chip,Ford SVO 24# injectors,Bosch O2sensor, Bosch in-line pump(w/stock pump), SLP 1 5/8" headers,SLP catback,short shifter,3:73s w/Auburn posi,170* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

 

the purpose of a supercharger is to increase air density, not airflow.

Swapping throttle bodies only makes sense if it is the worst airflow restriction in your entire system.
On a stock engine, I would look at the valve/bowl area of the head for the worst restriction.

ODB

 

I used 305 heads to keep compression up on 9:1 pistons until I can get afr 195 heads and a 125 shot of NOS. I though well I will build the bottom end now and what ever I can on top for the NOS when I did the rebuild until I ran out of money. It going in steps. I thought about a cheap set of 350 heads but I remembered what the 78 350's producing like 160hp was because they had no compression so I though better to keep compression up for now do some valve work and sacrafice air flow and save money.
I will be there one day.

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86 Trans Am 355 TPI Rebuilt 700R4 with Corvette servo, modified valve body, and a B&M Torque Converter (2000 rpm stall w/ lock up), 87 350 block bored .30 with new crank. Reworked 305 heads with 3-angle valve job. Added in the rebuild was an SLP TPI cam, BBK 58mm Throttle Body,MSD 6A, Hypertech Power Coil, 1.5 Crane roller tipped rocker arms, SLP Intake Runners and Port matching in upper intake including fully ported plenum, TPIS adjustable fuel pressure regulator @ 46psi, Hooker shorty style headers w/ Thermotech heat wrapping, Custom 3” exhaust with Flowmaster muffler and chrome quad tips, Hypertech Thermomaster Computer chip, K&N open element cone filter on modified MAF per TPIS specs, MSD Wires, removal of A/C hardware and added a 1LE firewall cover installed. Also there has been a PST front suspension kit with Hotchkis strut tower brace added. Soon to have Intrax lowering springs.
http://geocities.com/SunsetStrip/Garage/9548/kyle.html

Kills:
95 Talon TSI, 96 Probe GT, 91 T/A L98, 89 RS, 86 Mustang GT, 88 Mustang LX 5.0, 92 Thunderbird V8. couple or ricers that I think were Civics or Preludes not sure what year, 95 Celica GT-S, 94 Chevy 1/4 ton 350, one of those NASCAR F150's

The Third Gen Will Never be Forgotten

 

Swapping the tb does help, even if its not the biggest restriction. There are flow losses associated with every change - bends, larger/smaller transitions, valves (tb), etc. I'm sure you'd pick up more hp with a nice port job on the heads, but you will still get atleast 10 hp swapping over to a larger TB. If a 48mm tb has a pressure drop of 4%, and a 52 only has 2% (pulling random numbers out of the air), you will gain that much more airFLOW. HTH!

A.

 

Darn it people, why the hell do you need a 58mm TB when the RamJet 502 needs only a 48mm??? If someone could tell me this then they are smarter than me. And I don't want to hear any crap about the Ramjet could make more power with a bigger TB.

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1991 Firebird
350 L98 (was a 305 TBI)
T-5 transmission
Edelbrock TES and cat back
Accel manifold
NOS
subframes
jegster torque arm
MSD Digital 6
AFPR
Lakewood lcas
hurst linelock
SLP cam
relocated battery
cold air
Hypertech chip
centerforce clutch
poly bushings and mounts
etc..

14.1 @ 99mph with just headers and catback

with NOS and other mods???? twelves??

 

yes I realize that everything helps.
you can gain big power from a head swap or from putting headers on stock engine even though they both couldn't be the biggest restriction.

I was only generalizing.
sorry

 

The ramjet 502 cu in with 511 hp gets by with a 48mm (stock) throttle body. That IS some amazing ****!! It must get good MPG's too. Highly efficient motor.

 

...and I'll bet the ramjet would get more HP with a 52/58mm tb as well. It's like saying that the new f-bodies make awesome numbers with the stock exhaust, so you must not need longtubes and a catback. GM has millions of the 48mm castings bought, and they just don't want to spend the cash to make the 58's, or adapt the single barrel tb's. <shrug>

A.

 

Why do I need a 58MM TB?

Why make a restriction? I know it will flow all my engine ask for and a littel more, so when I get the AFR's, Put the NOS on and Grab 24# injectors and stack that onto a ported Eldelbrock intake. I will need all 58mm of it then.
I agree to the fact that the RM JET 502 gets by with a 48mm TB so GM can same some money. I know it could use more. If I had the eqations here I know I could work them out and show you that the 502 could use more air than what the puny 48mm TB is giving it, but I don't so I guess its just my word against yours and we will have to live with that.