I just bought some Motec injectors out of a 91 350. I am putting them in my 87 305. The 19# injectors I took out were a little longer due to what looked to me like a shield around the output end of the injector.
Do I have anything to worry about as far as spray pattern?

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'87 T-A 305 TPI
IN PEICES RIGHT NOW

 

I wouldn't do that. You've got to have some serious mods to run an injector that big on a 305. I'm building a 355 and I'm expecting around 330HP...still using 19# injectors. With the lower volume, you can run higher pressures to increase fuel atomization (more HP). Bigger injectors will limit your highest desirable pressure, decreasing HP output. If in doubt, opt for the smaller ones. 305's use 19#'s while 350's use 22#'s. I wouldn't run those unless you're making over 300 RWHP. You'll run WAY too rich...Also, the stock computer is set up for the 19# injectors, so you'll require a PROM change on top of that. Keep in mind...SVO injectors usually run less, so if you want new injectors, look into those. They'll work, I'll be using them, but I haven't used them yet. I've heard they actually have slightly higher volume at GM fuel pressures, so they will pretty much support whatever you can get out of a 305. Best bet- GM motec injectors cleaned and blueprinted @ 19#. I just picked some up on ebay cheap (with recipts). Look around, you'll find something.

 

The Multec injectors you obtained from the '91 350 are of the ball and seat construction, whereas I think your 19# are the pintle style. That explains the length difference at the tip. I agree with dh, you will run too rich unless you use an AFPR or better still, burn the prom to accomodate the bigger injectors. As far as spray pattern goes, I don't think you'll have a problem.

 

DHIROCZ is exactly correct. I have a set of 24# SVOs on my shelf at home because I don't need them yet. Check my sig man Im running a 13.9 right now with that set up

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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.
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Using an AFPR will not help at all. The point of an AFPR is to raise fuel pressure. It will do nothing for lowering the pressure, since that is regulated by the spring pressure.

As for putting them on the 305, I did that for awhile, and ran alright, just rich. I then started burning my own PROM, so that I could utilize the higher fuel pressure, without running rich.

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