I was wondering if the injectors from a 350 iroc are bigger than in a 305 iroc (will it inject more gas)??, and if they will fit in my 305. The reason is....i'm trying to add more power to my 305. If it will work and give me more horses then I will pick up a set at the junkyard.

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> 1990 IROC-Z (black)
> one of 3000 IROCs with a 305 made in 1990
> flowmaster exhaust
system with mufler bypass
> z-28 spoiler
> blue under car neon kit
> check out my site at: http://geocities.com/thickfacek/IROC-Z.html

> email me at thickfacek@nc.rr.com

 

Yes 350 injectors are larger than 305 injectors and flow more fuel but why spend the money on injectors when all you need to do is get an Adjustable Fuel Pressure Regulator and increase the fuel pressure to 50 psi. An AFPR runs for about $60 new and I have found them here at TGO for $35 delivered. You can find the following chart at TGOs FAQ also.

The stock setting is 42 PSI. Much track testing has showed that any type of
increase will greatly benefit both horse power and torque. Here's some dyno
testing on a stock 350 motor which substantiates those claims:
<FONT COLOR="red"><pre>
42 PSI (stock) 46 PSI 50 PSI
RPM Torq HP Torq/diff HP/diff Torq/diff HP/diff
------------------------------------------------------------------------
2250 237.7 101.8 254.9/17.2 109.2/ 7.4 275.0/37.3 117.8/16.0
2500 241.7 115.1 262.1/20.4 124.8/ 9.7 283.3/41.6 134.9/19.8
2750 241.5 126.5 275.2/33.7 144.1/17.6 297.0/55.5 155.5/29.0
3000 237.1 135.4 278.2/41.1 158.9/23.5 305.5/68.4 174.5/39.1
3250 233.8 144.7 278.9/45.1 172.6/27.9 311.3/77.5 192.6/47.9
3500 241.0 160.6 278.2/37.2 185.4/24.8 309.5/68.5 206.3/45.7
3750 246.6 176.1 283.4/36.8 202.4/26.8 303.3/56.7 216.6/40.5
4000 250.4 190.7 278.3/27.9 212.0/21.3 298.0/47.6 227.0/36.3
4250 251.6 203.6 272.5/20.9 220.5/16.9 289.1/37.5 233.9/30.3
4500 253.5 217.2 257.3/ 4.2 220.5/ 3.3 277.0/23.5 237.3/20.1
4750 245.0 221.6 242.1/-2.9 219.0/-2.6 266.4/21.4 240.9/19.3
5000 227.6 216.7 225.0/-1.4 214.2/-2.5 237.8/10.2 226.4/ 9.7
</pre></font>
It shows that by increasing the fuel pressure to 50 PSI, results in maximum
torque increase of 58 ft-lbs (along with a much flatter torque curve) and
a maximum horse power increase of 19 HP over stock. 46 PSI also provides a
noticable increase which should work well for day-to-day street driving.




[This message has been edited by whiteroc (edited June 08, 2001).]

 

Summit sells them from 60 to about 160 in price, Holley's was about 130 and could max out at 65 psi.

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89 GTA 350 - stock all the way. But came with goodies, 3.27, dual cats, alum shaft. Mods and Website coming soon!!!

 

YEs smaller injectors and more pressure are better anyways. Though fuel pressure is specific to the engine. I had a 355 running 19#/hr 305 injectors. It ran best at 46psi. Go figure, but that is all it needed.

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89 Trans Am Turbo 3.8L All stock 43,000 miles #1053 of 1555

Past Thirdgen:
86 Trans Am w/ built 355TPI with SLP goodies and too much other stuff to List. One sweet *** car, wish I would have had a good enough Job to pay insurance on three cars so I could keep it, but for a 89 Turbo Trans Am w/ Low miles, I think I made the right choice!