Hi im andrew this is my first engine build.

overall together... my goals with this car is to make a 350 gen1 turbocharged street/strip car set up, with +/-500hp.

my current ideas for the setup are based around a single t70 turbocharger with a blowthough quadrajet carb and summit turbo camshaft.

list of build parts:

350 sbc w/ 4bolt mains (w/ main gurdle if funds allow)
stock HD cast crank (or cast aftermarket 383 crank if funds alow)
chromoly I-beam rods
dished Hyptentic pistons w/ molly rings
summit flat tappet turbo cam and lifter set: http://www.summitracing.com/parts/SUM-K1104/
high vol oil pump
double roller timing set
OE 750cfm q-jet off of a BBC converterd to blow through
walbro 255lph intank pump w/ bypass regulator
summit dual plain intake: http://www.summitracing.com/parts/XYZ-PC22001/
89 305cid throttle body injection heads (minor port and polish)
stock size valves
stock ratio rockers (full roller rockers or roller tip rockers if funds allow)
stronger pushrods of some kind
ARP main and head stud sets
Fel-Pro gasket set
OE style main and rod bearings
HEI ignition w/ MSD coil & wires
one step cooler plugs
intercooler w/ 2.5-2.25" piping
exhaust manifold/piping made with a set of block hugger headers and 2.5- 2.25" piping to turbo and 2.5-3" exhaust piping

this will be mated to a TH400 (with a full reverse manual VB if funds allow) and a HD converter with a anti ballooning plate.

i've come up with most of this with the help of a friend that has built a couple motors and has experince with forced induction in all its forms.

question time!!

i really have no idea what springs/retainers the camshaft in the link above need, suggestions plz.

i also dont know what would be a good place to set the base timing, i was thinking 10-12 degrees retarted

i will also have some questions regarding the 383 if i end up going in that direction.

all ideas and suggestions are welcome!

THANK YOU for providing such a great source of information free to the 3gen community!

 

ive never really heard of anyone using that carb for blow through, not saying it can't be done i'm just not sure how the secondaries open under pressure. i guess the vacuum diaphram plumbs into the turbo inlet. just seems easier to use a holley mech. sec. i personally dont like the 305 heads on any engine larger than a 305. its like Shaq driving a mini. i recommend reading as many books on bulding your engine as you can before diving in. even then expect to make some mistakes

 

i personally dont think ur combination is good for turbo, first thing i would chagne would be the dual plane intake to a single plane intake for better air distribution, ditch the hyp. pistons and go with forged pistons and maybe some h beam rods, get a holley 650 dp modded for blow thru and a boost referenced regulator like mallory 4309 start out with around 20* timing and start from there, or get a msd box with boost referncing timing so you could control it a bit better. this setup will be good to about 580whp or so your limiting factor will be your walbro fuel pump and fuel lines oh and dont forget to go ARP everywhere

one more thing, ditch the 305 heads

 

Your build is not very good for a turbo setup. Here is what I would change.

A main girdle is not needed. A factory four bolt 350 block is good to about 600hp with the stock main bolts. With studs, it will take a bit more.

The aftermarket rods are not needed. RPM is what kills rods, and with a turbo, and that cam, you will not need to rev over 6000rpm.

Do not use hyperpathetic pistons. Buy some inexpensive forged ones, like the old TRW2441's. They have a 21.3cc dish. You will need it to get the compression down with the heads you want to use. Aim for low 8's/high 7's for compression if you want to run pump gas and decent boost. Running a lower compression ratio will make it easier to tune.

Get rid of the Q-jet, and get a mechanical seconday holley. I prefer single plane intakes for blow through turbos.

Don't use that pump or regulator- use the Aeromotive external pump, and boost referenced regulator

Those heads you want to use are no good for your combo. The chambers are way to small to get turbo friendly compression. Since you are buying rockers, an intake, and only have a small cam, I would go and buy a set of vortec heads, replace the springs and run them stock. You will be far ahead.

Run Trimetal bearings instead of the OE babbit. They are more resistant to high loads.

At the HP level you are running, a midly built TH400 will suffice. Make sure it has the good sprag in it, and good clutches. You won't need a converter with an anti ballooning plate unless you run a transbrake.

Your cam is pretty small - just get Z28 springs, and use stock retainers. Get machined locks as opposed to stamped. I like the change the valves to 1 piece valves while I am at it for a performance build. Nothing ruins your day like the head coming off of a valve.

Your total timing will be dependant on your chamber, compression ratio, amount of boost, and a bunch of other things. I like to have about 10-12 degrees initial, and about 12-14 degrees in the advance. Shoot for around 20 degrees total to start and carefully tune the car from there.

Remember to jet the carb up about 10 sizes on both the primary and secondary to start and tune from there. Rich is safe, but go lean once and you will break something.