Just wondering if anyone has any advice for tuning a 454tbi unit on a 350?? Im going to be doing this swap in the near future and was wondering what to expect in the tuning department. Im thinking that I will need to increase my Ae enrichment to offset the increase in air flow. But is there anything else that I should expect?? Just looking for some advice in advance. Thanks again.

 

What is your current set up? A lot of this will depend on that.

You will have to custom tune it, those bigger blades create a whole new dynamic regarding airflow and fueling. If you have a 700r4 you will have to fabricate TV cable provisions since I think all 454 TBI motors were mated to TH-400 transmissions which did not have a TV cable.

Are you sure you even need it? If you dont have a high performance motor there are plenty of other things that you should put work into before upgrading the TBI. I've got a 350 TBI with the stock 305 TBI unit under the hood of my Camaro, and I have a 454 TBI unit sitting in the garage waiting for a nice rebuild. But I'm not going to bother putting it on because I have a small cam and swirl port heads (stock L05, is that what you have? Its a pickup truck motor). I'm saving it for a heads/cam swap.

 

My current set up is a proven 285hp on the dyno with a carb. Now I know that isnt that much but it tends to like more cfm especially in the upper rpm range. Changing from 650 to 750 picked up almost 10hp and about 13lbs down low if memory serves me correct still. Also runnning the Rpm air-gap manifold wich is a dualplane design. And dual plane manifolds make best power with a slightly larger cfm. The combo is a basic 350 bottom end 4boltmain with Old school camel hump heads and 202/160 valves. comp XE256 cam/212/218 int/exh dur and 447/450 lift on 110 lsa. The heads do have some mild port work as well. Along with headers and msd ignition. Its pretty basic and I know that but I will be swapping in a Comp XFI268 cam and a set of Edelbrock Rpm cylinder heads in the near future and Im sure that the 454 tbi will be needed when that happens?? Thanks for the help again though.

 

I think there may be some problems with doin that, I was informed that it`s possible,but that it takes modification to the idle air routing in the throttle body, because the 454`s is completly different than the small blocks,, best thing to do is check out Xtremefi, cfm tech and see What they have to say, they have alot of resourese on this subject, I did`nt want the hassle of that so I just bought the 2 inch bore/750cfm throttle body that Xtremefi offers it was like 200 bills ready to plug and play, it`s a direct bolt on and is the same one that comes off your vehicle, all you`ll need is a new prom and your stylin`!!

 

It is possible. So you have a carb right now and are looking to convert to TBI? Does the car have any provisions for TBI such as wiring harnesses, sensors, computer, anything? If not you are going to need that.

If you do have all that you still are going to have to invest in some PROM burning equipment and lots of time learning to tune fuel injection because that is a completely custom set up, there is no such thing as a factory anything that will run your setup the way it should. Especially with that cam. There is tons of information on this forum as well as the DIY-PROM board regarding tuning TBI systems, you should check it out. Do some searching.

 

Sorry for the confusion about the carb. It was broken in on a carb and ran on the dyno with a carb. But its currently got TBI running it. And yes I do my own prom burning and tuning etc. Ive got it running really well but just looking for a little more out of it. I really appreciate the help again guys, Thanks. ITs being run by a 7747ecm with a 700r4 tranny and I use tunerpro and a moates burn1 along with winaldl for tuning etc.

 

If you have already successfully tuned your engine with the small block tbi you should have little difficulty changing to the 454 tbi. as far as the 700r4 tv conections simple swap the bracket off a small block tbi and weld it on to the new tbi. The quickest route to getting it to run properly from where you currently are is to swap your existing injectors into the 454 tbi. That is provided you have sufficient fueling and are only looking for the increase in air flow. Then you should only need to touch up some of the idle parameters, add some AE and possibly decrease the setting to activate PE at a lower throttle opening. If you choose to run the big block injectors you will need to set up you BPC and probably need to touch up many other setting that effect your BPW.