i was thinking that these flowtech headwers and y pipe that pep boys carry would be good enough for hi -po 305

i called them and the primaries r 1 1/2 and the y pipe connection 2 the cat is 3", i think if i get a dynomax 3" catback exh(without a cat) it should be enough for HI perf 305.I dont think im gonna get 300 out of it anyway.

im gonna prolly be doing the lt1 cam swap,port 87+tpi heads(friend has them lying around),edelbrock perf intake or equivalent........maybe roller rockers
and of course gear and tranny work

i am guessing that with those mods that i will prolly get 250 hp
and that exhaust should be enough,especially if 240 hp can be made with the factory exhausst...........


just wondering what u guys think.
would desktop dyno be able to fig this out?
i dont have it but i think i should get it

 

i had the pictured dynomax shorty headers on my 30 tpi and it ran really nice, i think 1 1/2 primarys are good enough for a 305,they are bigger than the exhaust ports on my heads,i am in the process of rebuilding my motor, so far the long block is all together , i have ported heads, intake, runners, and plenum, as well as siamesed the upper plenum and tops of the runners, i installed an LT1 cam (.0450 intake .0461 exhaust) and i have port matched everything, i bought the headers i have for $100 from avance auto, and i had a y-pipe made for $50 they were coated with a black coating that turned white,and burned off, so i sand blasted them and painted them with a high heat (1500 degree) paint, then i baked them in an oven for 2 hours at 450 degrees and below is the result
keep in touch with me and ill let you know how my combo woks out,

also the flowtechs w/y-pipe are a nice set, for the price, the reason i bought the dynomax ones was cause i got a 20% discount .

oh i also dont have a cat and i am running dynomax 3 inch catback

and desktop dyno is a cool program but it wont let you change things like header primary size and real specifi stuff but it is good for ballpark figures on what to expect

 

i have 1 3/4 headers on my 305, i shaved off 3/10's and gined 3mph form just the headers and y-pipe.

 

when u put on the 1 3/4 headers, was the previous exhaust a stock setup (ie. cast iron manifolds etc.) ? or did you have a different setup, also you didnt state what your combo is what motor trans gears etc. and what times do u currently run?

 

my times before headers and y-pipe i ran a constant 15.5@87mph. i put the SLP headers and y-pipe on and now run a constant 15.2@90mph. both runs were done with a flowmaster catback. when i ran the 15.2 it was a lot warmer outside than my previous run, so i might beable to get it a little faster.

oh yeah, it was stock maniflods and y-pipe with my first times.