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Tbi motor build....

79k20350

79k20350

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Ive seens a few of these threads but thought id aska few specifics. I need to rebuild the 350 i have right now and am going to go .030 over, cam (nothing to big) some roller rockers, intake (if its worth it) and a set of shorty headers and exhaust ,and a good intake. Off the top of my head just guessing its prolly a 300hp combo, maybe 350 tq? now as for the fuel system, i know these tbis arent exactly power firendly:rolleyes: what should i do as far as fuel system? i need a new throttle body, will one from a 350 be sufficent or should i slap one froma 454 on there? how bout an aftermarket one? also what abbout the pump? think it will be enough. Btw this is going in a 93 and needs to pass emissons, thanks guys!
 
wouldn't eexpect 300HP with just those upgrade. Heads and a cam would help. Have to be careful with cam. I would definetally get a cam though. Call up Comp Cams and Crane Cams and see what they recommend. I just tore apart a TBI 350 2 times because a friend put too large of a camshaft in it.
 
yeah i wasnt thinking anything big. 200hp is stock right? when rebuilt the heads will get a shave and a 3 angle valve job too... 300 prolly is a bit high i was just shooting from the hip. i dont need a whole lot but if im doing it i might as well get that little bit more.
 
79k20350 said:
yeah i wasnt thinking anything big. 200hp is stock right? when rebuilt the heads will get a shave and a 3 angle valve job too... 300 prolly is a bit high i was just shooting from the hip. i dont need a whole lot but if im doing it i might as well get that little bit more.
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don't really see the need for a shave on the heads. Shaving heads just becomes a pain. Need to shave the intake to match, overall I don't recommend it on something other than a race motor. Personally I'd look at a replacement set of heads and a nice mild cam. That alone would wake up your engine pretty good I'd venture to bet. Say these heads? http://www.sallee-chevrolet.com/World_Castings/Stock_Replacement_Heads.htmlWorld Products S/R Torquer
 
hmm thats got me thinking.... a nice 76cc should give some good torque.... cant find a price liste though
 
79k20350 said:
hmm thats got me thinking.... a nice 76cc should give some good torque.... cant find a price liste though
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you wanted to shave the heads to up compression and think using stock chambered heads would bea g ood choice? I'd gow ith the 64s and up the compression a bit(keeping it in the low to mid 9s).
 
my heads all over the place tonight, its been a LONG day. the only reason i said shave, might have been using the wrong termanology but just to make sure the heads were flat (guess i should have said decked:confused:) if they were checked out not to be true. 76 would be a little more pump friendly. mid 9's with a 67cc aint bad though. think its worth the bump. like i said im not looking for tons of power, and the better head shou;d help alot even without the bump in compression. hmm lots to think about.. oh yeah what should i do about the chip?
 
im thinking of tossing on the edelbrock mpfi, and appropriate(sp) heads and cam. got with the folks at edelbrock and the tech person said it should be around 290 hp or so. my block is punched out .030 over as well. just an idea. if i stay tbi ill prolly get some stuff from cfmtech or affordable fuel injection.
 
im not looking to dump 1200 into another injection system when the tbi just needs some tweaking
 
Go 383, vortec heads, al. roller rockers. The stuff can be had cheap enough if you know where to look. This motor is built with the same specs as gm's 383 ht (340 HP 435 TQ) but with a TBI system. Plenty of power if you ask me.:D

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what are you doing to upgrade the tbi system? Looks good by the way! :waytogo:
 
neverendingproject said:
Go 383, vortec heads, al. roller rockers. The stuff can be had cheap enough if you know where to look. This motor is built with the same specs as gm's 383 ht (340 HP 435 TQ) but with a TBI system. Plenty of power if you ask me.:D
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Which TBI system are you using? Do you expect to get the same 340hp 435 tq with the TBI? Also, where do you look to find 383 stuff cheap? I am very interested. Great looking engine by the way.
 
I bored +.30 with flat top pistons, stock heads, Edelbrock intake and performer cam, stock throttle body and am very pleased with it. I've bought everything I need to burn some new chips (and have experimented with a few) but to be honest it runs so well on the stock chip I doubt I'll improve on it much.
 
I found a good deal on a holley TBI (670cfm), and I have to use a 50 dollar high pressure TBI pump (~20psi). I got pistons and a crank for about 400 even, brand new, in box, from a guy who has his store on ebay. 30 over speed pro pistons and a scat crank. I spent about 600 on machine work (bore hone balance, etc.). I am also using a marine intake for TBI, but you can get q-jet ones to work with an adapter. A 454 TBI would work, but you would still have to have a custom chip burned, which I got one for a little over 150.

EDIT: I thinking I will have close to the same numbers. Im running 1.6 rockers on the exhaust and TBI (gm tests on carbs). So im thinking 345hp and around 450tq
 
TBI motor

Vortec heads are the greatest thing since sliced bread! Not sure if they make intakes that match vortec heads to TBI though.
 
arent vortec and tbi heads the same pattrn for intakes? if so would vortec heads be a good way to go. ive never really read up on the newer stuff. what is differant about vortecs? isnt it the shape of the combustion chamber?
 
TBI motor

No the angle where it sits between the heads is the same, its the bolts that hold it to the head that are at a different angle than the older intakes. I have read about people modifying them to fit though.
 
71 Blazer said:
No the angle where it sits between the heads is the same, its the bolts that hold it to the head that are at a different angle than the older intakes. I have read about people modifying them to fit though.
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thats right it has 4 vertical instaed of angled botl holes right? and uses like 8 bolt instead of 12? when i said differant shape, i meant combustion chamber
 
TBI motor

Not sure about the combustion chamber, but I do know that GM sells them for around $500 a pair and they flow way better than his TBI heads.
 
you can either get a gmpp intake $$$$$, a marine intake (no egr, less $$$) or get a carb intake (even less $$).

Vortec heads have different port shape and bolt pattern, 8 bolts and I think the port is like 1/2 inch taller.
 
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