with my lt1 cam would it be worthwhile to siamese my base and get some SLP runners to? any gains to the runner/siamesing or is to much for a 305? dont want to loose power or waste my time.

 

how far into the base shound i go?

 

another thing i was thinkin about is with lack of cubes i dont need as much air as a 350 so would siamesing with the SLPs kill my bottom end or what?

 

Do NOT Siamese the base on a 305 period. you already get enough flow through the stock intake ont he 305, 350's are the ones that need to Siamese.

If you were to Siamese the intake on your 305, and I will quote from TPI-ROC "you will lose you life blood" wich is tork. and you don't want to lose tork on a 305 lol.

I suggest getting an after market intake or porting and polishing the hell out of the stock one, but do NOT siamese it.

I have ported SLP siamesed runners that those do the job for me

 

Yeah, but tpi_iroc had a 355 powered car that ran mid 14s so i guess he was missing some life blood himself?

I have a stock 305 with a siamesed base on it. I lost a tenth on my 60' and 1/2 a mph with the swap in similar weather conditions. As to my excuses, i was running aired down drag radials with the siamesed base compared to real street tires, which IMO explains the 1/2mph away. I think the 60' can be brought back up with more tuning.

Beyond the numbers, i'd say it's noticeably less peaky, in the low 3k range, and it defiitely makes more noise in the 45-5000 rpm range where the stock cam dies. Missing it's life blood? Not hardly.

Would i recommend it to anyone else. Only if you're in the chip. And only if you have a good converter (or are stick as in your case)

 

you have your poinst ed, I personally wouldn't recommend it. but more power to anyone that does.

 

Burning my clutches the entire way, after addressing the transmission it made about a full second difference in time. Siamesing the base isn't magic.

 

ok so nay on the base siamesing, ill just port match everything, now should i siamese the SLPs or just port match/clean em up? i have a plenum project goin right now too, i took an extra and cut her in half see how this experiment goes i guess.

 

You can bring down the divider in the runners a ways if you want, and open it all up as wide as you can manage as well, its only the base siamesing (unless the runners are 100% siamesed as well) that I'm not a fan of.

Good luck

 

they call SLP runners DIY runners because you have to do everything to them.

What I did was take the rough casting off of the top siamesed part and make the siamesed holes a bit wider & about 2 inches deep, then gasket match the runners to the plenum & siamese plenum.

I did not and do not recommend Siameseing the lower part of the runners, for the same reasons as siameseing the intake, it will hurt you.

Widening the siamesed parts of the SLP runners and making them 2 inches deep will shorten runner length, losing a bit of tork but gaining hp & top end breathability. I shift at 5,500 RPMs and it pulls fine.

 

excellent this car should go a bit ebtter this season, cant wait to get her back on the road this warm weather is getting me anxious.

someone recommended i take the heads off and do bowl work to each chamber and port match the intake runners to the gasket, should i ? im kinda gettin impatient to get the car done, i dunno if i should take the time to do this especially if its going to take ALONG time.

 

Just find a set of used 305 heads in good shape, get them hot tanked and magnafluxed, then fully port and polish them, that way you can work on the heads & still drive you car around int he mean time. Hell, that's exactly what I'm doing right now hehehe.

 

check out the thread i just started (ie: 85 TPI heads vs 89 TPI heads)

 

Here's the way i look at siamesing the base. It's documented fact that it can help a lot on fast cars. It's also documented fact that it is at least damn close to breaking even on a completely stock car. Depending on your tune and where you are between the extremes and how you use the car will make all the difference.

 

well my 86 lb9 auto IROC with 3.23 gears, headers, and 214/224 cam goes 14.6 @ 96mph. the stock converter is way too tight for the cam i have. this winter i'm puting in a 2500rpm stall converter and if funds allow installing a set of ported 305 heads with 1.94 intake valves. i thought of siameseing the base because my motor has no real bottom end anyway, and i will have a converter. the car right now pulls to about 5000, but i think once i get a good set of heads on it and make some power with a good converter the car should go a low 14. i was just gonna siamese the base cuz i dont have any low end to loose really, and i cant afford a high flow intake. what do you guys think?