aqualung

I am currently planning to have a 383 fully forged blower motor built. Problem is I can't afford new heads. I want to keep my CNC'd LT1 castings. They flow real well on the exhaust side (233.4 cfm @ .600 lift) but they only have 54cc chambers. This requires me to use .31cc pistons for about 9.5:1 CR or .34cc pistons for about 9:1 CR.

How weak are SRP forged -31cc or -34cc pistons? Will they take 12lbs boost?

ANTI VENOM

I sure hope they'll take 12 lbs cause I'm going to use them also.
They probably won't take much detonation though. What alloy are yours. 2618? What length rod? These are all factors, but I doubt anyone can give you an exact number. They are good pistons though.

Bruce

SRP forged are pretty decent piston. They should handle 12psi with out problem. They are plentiful of people that using them on the F body board. Go with the 34cc to get your ideal 9:1 c/r. With the 9:1 c/r will allow you to run 12bls on pump gas with good tune.

bacardioil

jody your lt1 heads are 58ccs, unless you milled them to 54. lt4 are 54.4 i run a 31.6 cc dish piston, with ported lt4s but my deck is 0. 5.850 rod. .039 head gasket cr is 9.3 and a dyn cr is 8.03.
this is a 383 just putting together now. deck height is very important without knowing the deck height your not going to know the cr. if you want to lower the cr all you need to do is get a cam with a later intake closing. mine is 55. this is seat closing not at 50%. very hard for me to believe your heads flow 233 on the exh side. who ever told you that is putting you on believe me. not being smart,its just not happening.

aqualung

My heads are from Total Engine Airflow. The are CNC ported to Stage 2. TEA is a reputable company. I see no reason for them to lie to me. I would post my flow sheet if I knew how, but I don't, so I will type it out for you.

Lift Intake Exhaust

0.1000 68.6 54.8
0.2000 139.6 100.5
0.3000 199.8 142.7
0.4000 240.9 188.1
0.5000 267.6 216.9
0.5500 271.3 225.6
0.6000 278.1 233.4

Check their website at: totalengineairflow.com. They also list their base LT1 flow numbers which are slightly different than these which leads me to believe these are the numbers for MY heads.

They also show flow numbers for Stage 3 heads which flow even better but they don't sell those anymore. They used to be located in Bowling Green, Kentucky but got bought out by Summitt last year and moved to Ohio.

Total Engine Airlfow makes heads for some of the fastest Mustangs in the country. Check their website.

Although you offended me, I still appreciate your comments. I am trying to build my new motor right now and appreciate all suggestions and ideas.

bacardioil

jody,
sorry i offended you, but i have never hear of any lt1 head that can flow 233. thats why i am using lt4s. some of afr,s best heads dont flow that. the only reason iam not using afr,s is i dont like the deep spring pockets and oil returns. its not the flow # its everything else that counts. remember the one thing i said, deck height and gasket very important. get it right and the engine will fly get it wrong the engine will ping like crazy even at 9.0. if the deck and gasket arent right. getting the dyn.cr needs to be right and dont let any one tell you otherwise. just trying to help, a well built 383 cost money i know very well. but if you do it right you'll be a happy camper.
gene

aqualung

Gene,

I am very interested in your buildup. I am currently planning a blown 383. I will be contacting Greg at Blowerworks in due course. But right now I am having my shortblock built. It will be:

Splayed 4 bolt LT1 block bored .030"
Callies 4340 Forged 3.75 Crank
Callies Comp Star Forged 5.7" Rods
-31cc Forged SRP pistons
CNC ported LT1 heads milled back to 54cc
Comp 224/236 116 LSA .568/.586 lift

The deck height will be close to zero and I will probably use a factory gasket thickness of .049.

Do you see anything wrong with my combo? How does it differ from your combo?

How much boost are you running and what was your RWHP and TQ numbers?

I am hoping to run 10-12lbs boost and achieve 500+ RWHP and TQ.

bacardioil

jody
greg just finished my stock lt1 93 vet. we became very good friends. he worked on my car himself. at his home. we got the car to run 13 psi of boost. when i decided to use his system, i got his hole system with all the bells. he used my car as the prototype for the 8 rib pullie and bracket setup. he a great guy but you must listen and do what he says. its not cheap but it works. you cant find anything or see anything but the blatter bag. he did some job. i was very lucky. greg and i are going to dyno it soon we just dont want to blow it right now untill new is ready. i have studied this engine build for over a year and your close to mine. do not use 5.7 rods yes they make maybe 10 or 15 hp more but they also rub more on the cylinder walls. i went for the 5.850 pro mod rod good for 800+ hp. my piston are custom made 31.6. they are teflon coated on sides and ceramic coated on top. rod, mains, and cam bearing are also coated. that extra will pay off in the long run. less heat. 0 deck, .039 or .041 gasket. i hope your starting to see what im talking about. jim and burt greenwood are friends from greenwood corvette they build some cars. i have their new c4 body not an internet cheapo. the real thing. we are all meeting in Pa next week at the big corvette meet for 3 days. my vett isnt done as far as the body goes it would have been in their booth with their c6, c5, and my c4. great guys learn alot. your heads are fine. i have a crower cam, dave and me talked for weeks about it. small base circle use. dont look for big top end power. your driving on the street light to light get the picture. my cams 221/230 at 50% 525/545 lift on 114, 110 centerline. low and mid range and you can use the new comp cams beehive spring #26918s. my computer program put engine close to 600 at flywheel rwhp just above 525 with 10 psi. very late, if you want to know more email me at bacardioil@aol then ill give you my # gene

ostrich

Just wondering how you guy's are making out with the 383 builds? I have one in my Camaro, just detonated a piston. Bad tune! I have a 383 with a Scat crank Keith Black pistons, TFS head (done by TEA). I'm using a Vortech SQ approx 7-8 lbs. Just wondering what pistons you guy's ended up with, and also camshafts? Let me know. Thanks

Baldturbofreak

I use custom made -37cc shape 5 wiseco 2032 slugs. they provide 8.7-1 compression w/54cc heads. Mine are fully coated from swaintech and have custom made .210 taper wall h11 tool steel pins. Total cost? $1078! If you wanna play.......
I hope they're strong enough for the 32psi of alcohol burnin' boost.

ostrich

Wow. I'm running 64cc TFS heads, will only have appox 10-12lbs of boost. That thing must scream!

Baldturbofreak

I'm hoping it makes me scream as loud,lol

Hippiehead025

u mighth ave to watch goin with a 383 strokker s/c combo. I was gonna do the same, and i only had -28 cc pistons, and was advised by a top engine builder/engine supplier not to do so, b/c the piston skirts could possibly hit the counterweights on the downstroke. - Roger

Baldturbofreak

what would sc or na have to do with it? The dish has nothing to do with the skirt length. besides going to a 6" rod solves the problem. So does a crank that was meant for 5.7 rods.
If it were really an issue, the the 5.65" rod in a 400 would never work. and they have the same deck height as our Lt1's
Perhaps you misunderstood him, he was probably talking about how a large dish can result in not enough room of a long rod (due to the reduction in compression height.) IT won't allow enough meat in the crown for a strong piston, and it leaves the oil control ring hanging in the wristpin hole.
my motor swings over fine and has quite a but of room between the counterweights and the skirts. It's the cam that I had a problem with, which is why I had a small base circle cam ground.

Hippiehead025

yeah he said what you said, lol but he said also, even with the 6" rods and my crank, there would still be possibility to hit skirts on weights, im boostin using an Sc, so i'll just stay with 355, lol my 22 lbs will make up the difference. and as far as rods /cam clearance, eagle makes a clearanced rod that will clear the cam on sbc's - Roger