I have a really nice L-98 that I am working to put into my 91 Silverado, to replace the 200,000 mile 5.7 TBI motor that is in it. I got this motor through a purchase of a 68 C-19 Streetrod project and it already has the TPI unit refurbished by Street and Performance. The injectors have been upgraded and the motor has only 29,000 miles original on it. The motor came out a of a wrecked 90 Vette about 11 years ago and has been waiting for an install since then. I have went through the motor heads and lower end and it is ready for use. The motor also came with the wiring harness that S&P builds for an install into a streetrod. After a visit to those guys down there, I believe that it should be easy to interface the whole system into the truck. This install will increase my HP by a large magnatude and the alignment of it to my built 700R4 should be a good match. Has any one else done an install of this type?

 

I will be the first to let you know that all seems well when I datalog it, but it feels like I lost a good 30-40 ft/lbs down low for around the same TQ increase around 3,000 rpm. Then it runs like someone with asthma above 4,000.

 

So what are you saying? Did your swap disappoint you in the completion. I spent some time with Mark Campbell of Street and Performance (Mena, Arkansas) and he has a tuned port unit installed on his 92 daily driver. He said it was a good upgrade to the TBI unit and it opened up the performance on the truck. With the computer being programmed to his specs and the upgrade on the injectors that I have, the assumptions put the motor at about 280 HP, which is about 120 horses more than the 5.7 that is in the truck now.

What was involved in your install and what was it put into for a driver?

 

I wouldn't say that it was a complete disapointment as I COMPLETELY expected to lose the low-end torque. The little 305 is at 255 RWHP and is getting 20 MPG highway, but is a little less powerful on the highway in OD than the TBI. The trade-off was made for frequent towing purposes where the engine will see 2,600-3,200 rpm in 3rd gear pulling a 4,000 lbs traile, which it really helped do. For a Daily Driver not pulling a load, I would not recomeend it. I went from being able to rev out to 5,600 rpm to running out of steam at 4,800-5,000ish and this is on a 305.

My nearly stock TBI 350 with good tuning pulled 218 RWHP @ 4,600 and 339 ft/lbs @ 2,700 with Stock Cast Iron manifolds on it. That is very similar to your 280ish HP. My old 312 (.040" over 305) with TBI pulled 301 RWHP on a Mustang Dyno with the cut-outs open!

It is in a 1994 G10 Van with a 305/4L60E/3.42 gears that regularly pulls 4,000+ lbs.

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https://www.thirdgen.org/forums/dfi-...ml#post2974054