I have a '94 Chevrolet Suburban 2500 with a 350, it has 145,000 miles on it. Me and my father are planning on improving the performance b/c right now she is like a lead sled and the engine seems like its over worked with the Dune running we have been doing with it. What should I do with it? Some people have told me to replace the engine b/c its too old to subject to higher horsepower. So if there are some suggestions Id love to hear them,

Jonathan  Zeeland,MI

Swapping gears in the axles would really wake it up on the dunes, but may hurt mpg on the highway. Little things like exhaust, headers, air filter will help alittle. Fuel pressure regultors really wake up those mods on TBI trucks. If you feel you need it, you could get a higher flowing tb, but you probably dont. What dunes are you running on?  

Thanks for the advice. Would a cam help that much? Yeah, I run on the Silver Lake sand dunes near Shelby Michigan.

yeah your motor is getting pretty old either try and find a used one with lower miles or try and get it rebuilt you could even bore it out and then you could build it up from there  

Yeah thanks,  I'll run the ideas past my dad, and check into them.  

Have you and your dad thought about buildin an engine from scratch ? All you need is a good engine stand and and good 350 block to build on. Me and my kid were thinking about doin that, but his work schedule and the finances have not been on our side lately. We will probably do that at some point in the future. It's better to build another engine so your truck's not out of commission the whole time your build is in the works. - just a suggestion.

Thanks, me and my dad are in the same situation. Yeah, I dont want my truck out of commission while i work on it, building one is a good idea. Were looking at a  rebuilt 454 right now it only has 10,000 miles on the rebuild and the engine looks good so were interested in buying that and putting headers , dual exhaust and whatever we can afford to do. Thanks again for the advice. 

I bought the Flowtech (Holley) Afterburner headers for my 350, and just got done installing dual Flowmaster Super 40's with a cross-over (H pipe) (no cats) just behind the transfer case. The Super 40's kick ass!!They've got the deepest agressive sound I've heard out there, other than the Dynomax Bullets. I'm not sure I'd go with the Holley products again though. The quality is not very good at all. I had to do some finish grinding on my headers, and it seems like they come already rusting in the box. So far I've had no trouble with my Holley 750 cfm carb though, even though everyone tells me Holley carbs are maintenance intensive. I had to keep getting my holley 625 re-adjusted at least once a year before I replaced it with the 750 double pumper. The Rochester 4MV is bulletproof in my opinion. Good luck with your engine build!

Sweet! Thats the aggressive sound that i want for my truck. How much were those flowmaster super 40's?? It sounds like i want those for my truck. I have also heard about the quality of Holley carbs being subpar. Ive used edelbrock in the past and havent had many problems. Do intake manafolds really make that much of a difference? I have one on my current 350 and i really havent noticed a difference.  

The Super 40's ran around 70 bucks each at Jegs http://www.jegs.com . You may also want to look at Summit Racing, but their prices usually run about the same as Jegs. Jegs has better tech support though if you want to ask technical questions on any of their products. Summit you have to call long distance (instead of toll-free) and sit on hold a while.

Intake manifolds can make a big difference in power but they can be a bit tricky ( like cams ) if you don't get the right one with the other equipment you have - lifters, rockers, carb, etc...  Some manifolds are better for high end torque with high horsepower engines, and other are better with low end torque with average hp engines. The spectrum is vast.

The safest way to go is to get 'system matched' parts from one provider unless you trust the 'expert' making the recommendation on purchasing individual items. I've gotten burned by so called 'experts' in the past. Just because a guy owns & runs a "performance" 4X4 shop doesn't mean he knows a pinion angle from a hole in the ground. I learned the hard way and ended up doing it all myself with a lot of advice from an assortment of folks.

I wouldn't recommend Holley products at this point. Carter was bought out by Edelbrock I heard, they are pretty reliable. The Quadrajets are the most reliable carbs in my opinion. Holleys have to be adjusted pretty often and the carb bases are not true planed sometimes. I had a mechanic who said the first thing he did with any new Holley carb was to have the base ground perfectly flat by a machine shop. He was a magician with my Holleys to be sure.

Cool, I'll look into getting my self some of those. I have purchased some things from jegs and summit racing before and they both are relatively good. Im probably going to get a used rebuilt 90's 454 from a guy and put dual exhaust on that, do you have any idea on what is involved in swapping a 350 with a 454, im just wondering to how long it would take and how labor intensive it will be. thanks  

I don't have much info on small block to big block conversions. Probably someone line 'blackchevy' or 'malberg' could offer you some help with that. You may want to post a new thread on that subject if you don't hear from them on this one. You will probably need to look at a tranny conversion too. Possibly a TH400. Sorry I wasn't much help on this one.

The tbi 454's are not all that great. If you really want to do it, you will probably need the mated tranny, or a 4l80e or something along those lines. Need the computer with the motor, or better yet have a chip custom burnt for you.

If it were me and the 350 block was in good shape, I would rip it down and rebuild it, and if you really want more power, make it a 383, it will be torn down anyway, just have a machinist get the block worked down for you.

Alright then. The block is in good shape with only 145,000 miles on it. My suburban already has the 4l80e transmission in it. i have been told thats the better transmission of the two. Making it into a 383 sounds good to me. Sounds like a lotta work but its worth the better performance! You know what your talkin' about more than i do so I'll do what you recommend. I'll get on it as soon as i can. Thanks  

Thats alright dude, thanks for tryin' anyway!!