[v8mazda]

I've been on here lately getting the skinny on my heads i was using for my build and..... well I'm kinda having a change in heart about my build. i have some extra dough and am kinda thinking about going turbo. could anyone give some basics about building this kind of motor. such as, what kind of compression should i be running, what kind of cam, whats the best valve train for this kind of motor. i know my question is kind of broad but I'm just looking for some input which will give me some direction as to where i can start looking. or maybe someone knows of a build i could follow. as far as what I'm working with.

-86-88 4-bolt main block .060 over(fresh).
-flat top pistons and i DONT know the compression as they came with the block and i need to find out(if anyone knows how i can do that it would be a help)
vortec heads, port matched,bowl blended, performance valves,with beehive springs
-crosswind intake and edlebrock carburetor.

i have not purchased the cam and lifters yet or the turbo kit.

thank you to anyone who chimes in.

[v8mazda]

bump for any info, anybody.....

[ap72]

you need different pistons. D shaped dish, forged, shoot for about 8:1 compression. Cam should be less than 225º duration at .050" on a wider LSA (112-114), and preferably hydraulic roller. lobe split depends on the turbos used, will probably end up around a single pattern or a small lobe split (6º or less).

[v8mazda]

thanks for the input. it gives me something to start with

[NXS]

I currently have a late model GM long block, ported vortec heads, roller cam 230/230* & 470/470, air gao intake.
It went 12.62 @110 in my vette on 87 octane, street tires and 3.07 posi

here is a vid of the car with stock manifolds on it and a Q-jet

http://www.youtube.com/watch?v=SAi2ablaEbM

I have both headers made and an ebay turbo, y2004k (gt45 haha)
It is close to 9.8:1 compression I think and with iron heads I'm not sure how much boost I will be able to push through it on pump gas and no intercooler (I do have an intercooler but I'm having fitment issues with it so.... unless I just have to have it I'm going to forget about it for now.)

If you want to keep updated on it send me your email in a PM.

[v8mazda]

interesting, maybe i'll just do what you have lol. was it hard putting it all together i know my way around motors but i'm no mechanic.

[zildjian4life218]

Originally Posted by v8mazda

-flat top pistons and i DONT know the compression as they came with the block and i need to find out(if anyone knows how i can do that it would be a help)

http://webpages.charter.net/beckracing/slvpg28.htm
scroll through those. That should get you a better idea of what pistons you have. But like ap said you will likely need forged. I am currently building a turbo 305 with stock cast pistons but I am running piston oil squirters and will be running 8.0:1 and an intercooler. So hopefully my pistons wont come apart too quickly. IMO i would never run a carb on a turbo engine. It would be so much easier to run fuel injection. More expensive but better in the long run.

[matt167]

keep the boost low and cast pistons won't mind.. boost around 5-6 psi, assuming a comp ratio of 8.5:1 will be just fine, and should add ~100 hp

[v8mazda]

well i plan on getting new pistons. someone told me there are two kinds to choose from. i was just going to call up summit and see what they have. sounds like it comes down to low compression, forged lower end, and a cam like mentioned in the thread.

[ap72]

Originally Posted by v8mazda

well i plan on getting new pistons. someone told me there are two kinds to choose from. i was just going to call up summit and see what they have. sounds like it comes down to low compression, forged lower end, and a cam like mentioned in the thread.

There are probably a bout a thousand different pistons that will fit that block... I guess by two you mean, the right kind, and the wrong kind?

[v8mazda]

yes i think the person was talking about type of material used for the piston

[zildjian4life218]

Originally Posted by v8mazda

yes i think the person was talking about type of material used for the piston

theres cast, hypereutectic, and forged. hypereutectic are actually cast but have more silicon in them which makes them stronger but more britle.

[v8mazda]

forged would be the best right?

[zildjian4life218]

Originally Posted by v8mazda

forged would be the best right?

i would say yes. but that depends on your hp goals and how good u r at tuning. the thing with forced induction applications is that the cylinder pressure is so high the chance of detonation is very high so a good tune is a must

[v8mazda]

ok i know I'm not good at tuning I'm not much of a trouble shooter. i can put stuff together but that's about it. so maybe i should look into that as well before i start.