ok many of you may remember me as the guy who was going to be forced into degrading his iroc by putting in a v6. not a prob anymore..... i have a 350 block and heads all ready and waiting for a cam to drop it in my car. im looking to get 400hp or more when im done. any suggestions on what i can do to get as much power as is streetable would be greatly accepted. SO FAR.....

350 bored .030 over
305 heads (smaller chamber=higer compression)
MASSIVE VALVES (dont know what size but they are huge)
high comp pistons

looking to get a lunati cam with about a 460 something lift and duration in the 280's

maybe getting some headers
definitly going true dual flowmaster 40's

my first time building up a sbc so you guys probably know a lot about how to sqeeze out those hidden ponies. any advice would be greatly appriciated..........
oh and its a tuned port

 

Congrats on the new engine. Just a few things I would like to point out, and it doesn't mean I'm right. Be careful with your compression, with those little 305 heads and high compression pistons that won't really be streetable. Your compression will be so high you will have to run race gas so you don't detonate. Also I don't know how much power you can get out of those heads even if you do put bigger valves in them (someone else will chime in here). As far as the cam I am not really sure, I guess it depends on what you end up using for heads. Headers are a good idea, but stick a single muffler setup. Headers and a flowmaster 80 series will be more than enough.

I'm sure some of the other guys can give you a lot more info.

 

I dont know what kind of "high comp" pistons you have but the 10.5:1 flattops usually are only 10.5:1 WITH the 305's 58cc's so you should be fine there. If you are running the stock TPI system you will be fine there too because the TPI system cant outflow a stock 305 head anyhow. also if the 305's heads have had bigger valves put in them the seat is usually cut to fit them on a Serdi machine during this process it is nearly impossible to cut the seat without opening up the side of the chamber. commonly this is referred to these days by the fancy name of "unshrouding", but basically it is a required process for cutting a bigger seat in a small chamber head.

 

Thanks for clearing that up Tom. When he said "high comp" pistons I figured he was talking about some sort of domed race pistons.

 

I do want to mention that the 85 305 heads are a little short on flow compared to later models and should be gasket matched to fix the biggest problem they have. many later 305 centerbolt heads (late 86 and later) flow more than the 85, early 86 models. also the 350 centerbolt heads come in two versions, one has a "pushrod clearance" bump in the side of the runner opening and the way later models dont, as far as I know this only applys to the iron L98 head because the truck 350's have the bump. I feel these latter 350 heads could have something to offer especially over the 85 305 head. I dont want to mislead you about the problems of using the 85 305 head as far as flow goes, and like I said because of unshrouding to put larger valves in it probably has been opened to 60 to 64 cc now that the larger valves have been put in. The valve size of my 85 TPI heads stock was 1.84/1.5" which is not that terrible considering most 305s got the 1.72/1.5". Every one loves to talk about the S/R torquer II 305 head with its 1.94/1.5 that has the closer valve placement to fit them in a 58 cc chamber and into the bore of a 305. But a head not to forget is the L31 Vortec 5700's little brother the Vortec 5000 (L32? L30?) is the 305 and it has high flow vortech port design, 58cc, 1.84/1.5 valves makes a potent head and Im curious to how it would perform on a basic TPI 350 but remember to run it you must have the new lower that fits the vortec heads.

 

yeah the pistons i have are just flattops. no dome. but the guy that sold me the "kit" (block heads and rotating assy.) said it would be about 11:1 comp. also, if i use the 305 tpi setup it will work with a 350 right? i mean the computer wont know the difference will it?

 

There are a few small issues here w/ the 305 to 350, but nothing really hard or expensive. Your best bet is to do a search and you will find tons of posts on this topic, search under the TPI forum.