im planning on building a high horse(550) lt1 im planning on using headman d port long tubes 1 5/8 primarys(i know a little small but affordable for now) dual 3 into a single 4inch to a spintech in back. now the queston is untill i do the swap, can i put that on my 305? and will those headers fit? just wondering

 

Yes you can put that on your 305. Might lose a little torque down low but it should work fine.

 

Unless this is a race only vehicle, 4" is too large. You'll loose the scavenge affects and subsequently low end, possibly mid range torque Will suffer.

 

550hp will need 1210 cfm of flow. Single 4" flows 1440cfm at 28" of H20. I think its a good match. Dual 3's flow more like 1625 cfm total and would be abit large for a 550hp machine but not horrible. Dual 2.5's however flow 1130 cfm and would be a touch small.

Keep in mind with a single exhaust you need one muffler that will also flow as good as the straight pipe. Dynomax ultraflo rounds, bullets, magnaflow straight thru, borla straight thru, and other straight thrus should do it.

My street 383 loved single 4" exhaust. Sounded great too. No lack of power anywhere. I would estimate 500 crank hp based on 400whp thru the automatic trans but it may have been closer to 550. It was a strong motor.

My turbo car now has dual 3" on a 9 to 1 compression 401" motor. Mild hyd roller cam, and it has plenty of low end power when normally driving. Feels fine to me even with 2.73 gears and a loose converter which is close to 4200 stall. I dont think you can go too large on the exhaust that it would kill off a drastic amount of power.

 

i know what you are sying. that set up(headers,dual 3, single 4) is for my 383. but untill i build it, to get it out of the way can i put it on my 305?

and i know that from research, that spintech is not the best flowing, i understand that BUT i got a deal from someone on here and i really want the sound that comes from them

 

you think these will fit my 305? http://www.summitracing.com/parts/HED-68469/

 

or on my 305 ill just put it in and somewhere ill neck it down to 2.5 and back up to 4

 

Almost all SBC headers are the same & they will fit 305,350,383 etc. Yes they will fit your motor just dont get the cheap painted ones.

 

well im talking about port type.

and i can only afford cheap paint now..... i might get them coated later. or buy 2210s

 

If do go with those long tubes check the clearances around the rear K-member and A-Arms. I had to take off a notch on driverside back mounting tab to get my Hooker super comps to fit. (there dented from previous owner not clearancing them on there car tho).

 

If you check under applications on the tab it shows what they will work with. They have 305s and 350 listed of course. Should work fine.

They may require a ministarter depending on how much room you have in there. I know I had to take the mini-starter off, install the passenger header then wrestle and install the starter again.

 

what type of headers / ypipe did that street 383 have?

 

now what happens to flow on the 3 inch if i oval them to clear subframe