TBI rebuild?

[jimmy'sjimmy]

is it worth it to rebuild a TBI engine with the factory heads? i know the stock heads are horrible but i dont have enough to swap them out yet. the motor has 170k on it and i want to rebuild. would it be a waste of money to use the stockers now and when i save up enough do a head swap? if i do use the stock heads what is the max lift i can go with on a cam? i really really want to rebuild it myself but i just want to make sure i dont go wasting money i dont have.

 

[1979jimmy350]

you can always port them to gain some pretty cheap power gains

 

[Cricket]

If you plan a keeping it stock you may as well rebuild it. If you want more power get a set of newer vortec heads with the vortec TBI manifold.

 

[fatbob]

Stock TBI heads are great for many of our uses. I don't want to start a long arguement about which heads are best, but IN MY HUMBLE OPINION , people who say these heads are horrible are looking for power in the upper rpm range. Since I seldom go much over 3500 rpm, these heads work great in the low rpm range. So figure out what range you want your power in, and match the cam to it. Stock heads and a RV cam work well for me.
But if your into muddin you might want a bigger cam and heads. It depends on where you want it.

 

[tarussell]

Stock TBI heads are great for many of our uses. I don't want to start a long arguement about which heads are best, but IN MY HUMBLE OPINION , people who say these heads are horrible are looking for power in the upper rpm range. Since I seldom go much over 3500 rpm, these heads work great in the low rpm range. So figure out what range you want your power in, and match the cam to it. Stock heads and a RV cam work well for me.
But if your into muddin you might want a bigger cam and heads. It depends on where you want it.

x2 !
Only thing wrong with the O.E.M. stuff is thin castings - just make sure that they are not cracked. Good heads for stock type motors where low end power is sought after.
Tom

 

[jimmy'sjimmy]

well i am planning on running some 40s in the future and i mostly run in sand and mud so the mid range power would be helpful. i dont do much rock crawling or really slow stuff like that. im going to put 4.56s when i swap the front axle out too. so i guess ill just build the short block for now and buy the vortec stuff piece by piece. ohh another ? will the gm performance manifold for vortec heads fit a 50mm tbi?

 

[R72K5]

yeah these little swirl port style TBI heads are not for high RPM, but plenty good for stock though

i think i said that right

if it were my engine i would get a set of carb 305 heads or old 307 or 327 heads and change the angle in the intake center holes and run it that way

but thats just me

everyone has their own opinions, etc


good luck

 

[dyeager535]

Does it NEED to be rebuilt now?

If it doesn't need to be rebuilt, don't pull apart a perfectly good motor when you don't have funds for some improvements, like heads, cam, intake, exhaust, etc.

My opinion anyway, if it works good and you mess with it, likelihood is it won't work as good afterwards lol.

 

[bigred81]

My two cents worth get a different motor to play with and drive the current motor till it gives trouble. Try to find a 90-92 police caprice motor because it comes from the factory with flat top pistons, fairly good roller cam, and higher tension springs for the roller cam. I did this in a buddies truck boy did it run good and it worked with the factory programing so no tuning had to be done. I also put one in an 86 S-10 with the factory fuel injection and run it at the truck very now and then. Last run it turned an 11.7 in the 1/4 mile with the stock heads, manifolds, and factory programing. Anyways this is my opinion.

bigred81

 

[4xcrazy]

Why rebuild it already???

mine has 235k on it, and still runing pretty darn good, smokes alittle at start-ups, but we all know what that is.

just keep it maintained, and change the oil REGULARLY, should run fine.

i personally only run 20/50 to kinda sorta help out with the "loose" seals and whatever, doesn't give me any problems, and i, at times, do "get on it"

i would do as mentioned before, get another engine, play with that, build it the way you want, and run the current till you REALLY need it.



and another thing,,,,CARB'D 305 HEADS??, you mean the heads that raise your compression, but do not flow worth a crapola?? worse than stock 350 heads???

yes i do know, i have them on another 350 with a fresh rebuild, only put them on, cause i NEEDED the motor running, and thats what i had.

 

[jimmy'sjimmy]

well i want to rebuild now because ive been working at a dealership while i go to school. im going to graduate in may and i wont be able to just rebuild a motor with experts looking over my shoulder when i feel like it. i have an 06 silverado to drive (early grad present) so im not worried about it being a dd anymore. maybe i shoulda mentioned that first lol.

 

[Thunder]

and another thing,,,,CARB'D 305 HEADS??, you mean the heads that raise your compression, but do not flow worth a crapola?? worse than stock 350 heads???

A big YES to that statement. Don't put 305/307 heads on a 350 as someone recomended. 305/307s have a smaller bore than a 350. 350s have a 4" bore,305= 3.5", 307=3.80" The combustion chamber on those heads is designed for that smaller bore. Putting 305 heads on a 350 just shrouds the patheticly small valves and screws up the flow even worse than it already is..

Stick with your TBI heads they are good heads for a truck. beings you said you work with some people who know what they are doing Maby someone could help you out to do some minor porting to them. You can pick up an easy 20+ HP just by port matching, smoothing out the casting bumps in the intake runners, and cutting down/smoothing the big bump that is casted in there to swirl up the fuel mixture. It is really an easy job all you need is a die grinder, carbide burrs, and a little time.
Also be careful how much cam you put in there. Unless you want to get into chip work. Use a computer frendly cam that will work with the stock chip. Check your block it may be already be drilled for roller guides. If it is. A computer frendly roller cam is the way to go