Upgrades for an old engine

[KWA]

Aloha everyone.

I have a 91 suburban 3/4 ton tbi with about 190,000 miles on it. It runs okay, smokes on start up, but its still going. I will probably buy a crate motor when it gives up the ghost. Its our family hauler nothing extreme, except a 4inch lift.

I want to mod it a little with the intention of using those upgrades on the new crate motor whenever that happens.

Question is; are there any mods that may not work when I get the new motor? Or maybe a better question is should I just what till I get a new motor?

My thoughts on some simple upgrades.

- Headers (Shorty heedmans?)
- After market exhaust (Flow master?)
- Aftermarket ignition, coils, distributor, wires (MSD?)
- Up grade TBI?
- Possibly a Chip?

Just in the planning stage but open to suggestions

 

[K85 Octane]

save the money and keep thinking, but don't act until you have a new motor

that's how you lose money and projects get sold

 

[badmix]

I would find out what would and would not void the crate motor warranty first.

 

[manchildau65]

Why buy a crate engine????? Sounds like your valve seals are old and leaking... that's why you only get smoke at start up.

How's the oil pressure? If you're maintaining decent pressure (20+ when warm at idle), then just give it a quick top end rebuild... If your oil pressure stinks then pull the motor, change out the crank (or get your's turned down but it can be cheaper to get a replacement), put new bearings in it, and then give it a quick top end rebuild (cam, hydro lifters, cam bearings, and head clean up / rebuild). Of course you're gambling with a few things such as the integrity of the block / heads and how the bore of the block is (major scores or a ridge).

In other words, if you somewhat know what you're doing then do it yourself and save a bunch of cash... plus it feels pretty good running an engine you built yourself

(warning: things can snowball... depending on how much power you want to try and make)

 

[sweetk30]

best tbi mods are these basicly.

stock cam SUCKS good swap in is a lt1 350 cam. but get the roller lifters/link bars and spider also then drop it in with new roller timing chain set. and set of old style z28 valve springs. and smack on the good umbrella style valve seals at the same time.

then drop the whole exaust off manifolds down thay suck.

go shorty headers. the 88-98 305-350 shorty headers on evilbay are cheep and tiny mod on left frame rail to clear.

grab a flowmaster scavanger y pipe section for around 50 bucks for 2x 2.50 inlet and single 3"+ outlet. have local exaust shop fab up the y pipe with that or do it your self. then goot highflow cat and muffler. this exaust alone will get you just over 40 hp and 50ft lb tourqe on the dyno sheet at the rear wheels.

also the cam swap will require small tune. contact brian at www.tbichips.com he has made lots of chips for this mod and has good info and help.

that stock lt1 roller cam/exaust / and mabye roller tip rockers ust 1.5 ratio will wake that thing up.

 

[oldtoyboyd]

http://www.cfm-tech.com/
upgrade for the tbi

 

[shovelbill80]

this is exactly what i'm researching right now....in a month or so i should have the money for an exhaust. the cam choice is very important to match the computer and driving style. almost everything i do now at 170K will have to be able to be reused with a roller motor......kinda like this one, and i spoke to Scott already too.

http://www.tbichips.com/lknspeed.htm

but i don't think i want the 44 muffler.....maybe a bit lower volume

 

[Big Ray]

this is exactly what i'm researching right now....in a month or so i should have the money for an exhaust. the cam choice is very important to match the computer and driving style. almost everything i do now at 170K will have to be able to be reused with a roller motor......kinda like this one, and i spoke to Scott already too.

http://www.tbichips.com/lknspeed.htm

but i don't think i want the 44 muffler.....maybe a bit lower volume

I used the Flowmaster big block series muffler on my old 89 pup...ran great, much quieter than the 44 series

 

[sweetk30]

flowmasters 40 series = loud inside and out

flowmasters 50 series = little less loud outside and lot less inside

flowmasters 70 series = noticable diffrence from stock but real quiet from a 40 series.

and add the delta flow option to make it smother and more quite

here is there sound level graph and links to muffler sound bits on vehicles. http://flowmastermufflers.com/index.php?cat=1

i had a pair of 40 delta flows on a 5.7 vortec in 96 crewcab. 3" in/out was good sound but more than i wanted in the cab. almost 4 years later rust from winter and salt rotted them out. i got a nice bolt in duel in/out 50 suv made for these trucks and much much better inside. and still great sound outside.

and i like the sound of a single flowmaster better than 2 mufflers my self.

 

[shovelbill80]

flowmasters 40 series = loud inside and out

flowmasters 50 series = little less loud outside and lot less inside

flowmasters 70 series = noticable diffrence from stock but real quiet from a 40 series.

and add the delta flow option to make it smother and more quite

here is there sound level graph and links to muffler sound bits on vehicles. http://flowmastermufflers.com/index.php?cat=1

i had a pair of 40 delta flows on a 5.7 vortec in 96 crewcab. 3" in/out was good sound but more than i wanted in the cab. almost 4 years later rust from winter and salt rotted them out. i got a nice bolt in duel in/out 50 suv made for these trucks and much much better inside. and still great sound outside.

and i like the sound of a single flowmaster better than 2 mufflers my self.

thanks for that link.......i think as far as sound goes i'm going to choose the 70 series big block II....i guess it should fit in there. i like a nice single as opposed to duals too.

 

[sweetk30]

no problem.

the upgrades thay say work. but getting in to motor will req chip redo. possible fuel pressure spring swap.

 

[KWA]

Mahalo for all the input.

I'm going to do a little more research on the rebuild suggestions.