williemon

I have been given an LT9 350 truck engine that was used maybe 5000 miles. It was bought brand new a couple years ago and was used in a comercial truck. It started running rough and smoked from one bank. It was swapped out for a new one and set aside. Now its been given to me to replace a broke 305 LG4 in my car. I did search on the web for chevy LT9 and found a few truck sites that listed specs for it. It is speced at 160 HP and 260 lbs/ft torque. I was a bit surprised cause my 305 specs at 150 HP and 240 lbs/ft torque. Whats the deal here? I read on this board a post from Five7kid that these engines had wimpy cams, heads and pistons. Is this so? Is the block the same as one for a car 350? What would need to be done to make it into a 240 to 300 hp 350, Head and cam swap, just cam, or head, cam and pistons? Will the components like intake with 4bbl Q-jet fit and the distributor? How about a flywheel? Would this block be a 4 bolt main? Looking for advice and any websites yall might know that will be a good source of info.

mystikkal_69

iTrader: (2)

what kind of fuel induction system was on it?
tbi? if so, yes change out the heads. since tbi heads were the swirl port design to increse lowend torque and gas mileage, they are no good for a perfomance application. definetly change out the cam. i'm pretty certain that you can you a carb setup on that engine.

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86',88',89' IROC-Z, 350 TPI, 700-R4

94' Formula, LT1, 6spd

8Mike9

There's probably only 3 things that may be different with that engine vs. say an L98..cam, heads and pistons.

You can make of the CR with the right set of heads if the pistons are different, but a new cam would be in order also. depending on whch pistons are used in the block, even a swap to L98 heads and an L98 cam still may not yeild the equivalant engine

rezinn

However.. a set of L98 heads and an aftermarket cam could put out more power than an L98. It might be a good idea to have the heads milled to raise compression if you do get a set with large chambers.

SSC

Yep a whoping 160hp. Your looking at a great builder though. The heads are 76cc, not very compression oriented I beleive it produces 8.5:1. You Could just slap a good set of heads pref, 64cc 194 with vlaves, and a 214in 224exh@.50 cam in it and you got a GM base HO clone, 330hp. That wouldent be to bad for a few $$$.
SSC

johndinu

you never said what's your budget because it's one thing getting 220hp (like the 305)out of this engine and other thing($$$) to get 300... and do you need only power at high rpm, or low end torque also?

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'89 GTA
Flowmaster animal

williemon

I found out a little more about this engine. The pistons are JUNK!! They are dished and they are damaged. There are chunks of the piston head that are gone exposing the top ring. Its like this on 3 of 4 pistons on the passanger side bank. All 4 look like somebody went after them with a hammer and screwdriver. On one, there is a piece of the piston fused to the top of the piston. The drivers side bank seems to look ok. This will be a complete tear down and rebuild. SO.....If My goal is a fun streetable and durable engine that will make HP and torque, Low end torque as well as upper end HP, What should I be looking into doing? I want it at least somewhat decient on fuel mileage, streetable cause it will be driven on the street at least 2 times a week, and durable, but I also want to try a little bracket racing. Not much, just enough to say I have done it just for the fun of it. If I win some races, fine. If I dont, fine. Opinions?? If you could spend my money, what would you do and why? Just say you had $2000.00 to play with, but you did not want to spend it all just to add 5hp. What would you do????

SSC

I would suggest you look into a summit rebuild kit. If your pistons are that chewed up you'll be lucky to get the walls clean at 30 over. Rebuild kit and some decsent heads.
SSC