LPE 403

iTrader: (6)

Grave diggers! Nice old thread...

CAMSTER

iTrader: (10)

274 cc are best for the street strip car lmo.

denscor

I heard that also! I was going to buy the 305 but was told 274 would work better for me. But my car is forced air car.

slippi84

iTrader: (4)

It depends on what size motor you have and where your reving out to.

7second

iTrader: (1)

LSX for more than one reason! and I have owned the mast.....

slippi84

iTrader: (4)

Pleaae name some id lile to know from people with expeeience cause I'm thinking about this too

CAMSTER

iTrader: (10)

Ok, cat out of the bag please, just for the rest of us, will you tell us what the reasons are, just so we know, thanks.

lazaris

iTrader: (5)

Could you elaborate more?

denscor

I would like to know also.

slippi84

iTrader: (4)

IS there any useable info on this other than people just saying this or that? I'm curious if these 305 heads kill your low end to supply top end power or if it's a good increase across the board because it would only cost me like 500 to get my LSX LS7 heads ported and polished.

njc.corp

the problem is this-not many sets of 305 cc heads out their-

but most of these 305 cc heads are going on 427+ and most of them are top end street or race applications-

i would say with a big engine-good compression like 12.0+ the low down trq would be great

i know of 2 x 305 cc builds going on at the moment and they are not ready at all-

slippi84

iTrader: (4)

I have a LSX 454 crate motor with 11:1 compression GMPP LSX LS7 intake manifold 6061 elbow and 102NW TB so I have the need for a good flowing head up top but this is in a Trailblazer which is a tank on wheels so I don't want to lose my low end. If these heads on a 427+ engine still do good down low and make big top end power they would be worth it for me. Other wise I'll just port my LSX LS7 heads and call it a day and live with my top end how it is with more low end.

MOZEZ

there are a ton of 305 heads out inthe field running. They are not 305 cc. That is a series number. They just have a larger 2.250 valve than our 285, which is 280cc with a 2.200. They are 288 cc. They will not hurt low end at all. The cross sectional area is still reasonable. Nothing to worry about. good luck with your build.

Cary

slippi84

iTrader: (4)

Now im confused lol. The Mast heads say 305cc are you ssying that other companys make heads that are the same just wirh smaller/larger valves?

REGALIS

Thanks for that very educational post.. Without information what you've had means nothing....

scphilli

iTrader: (2)

+1, I have a set of these on order and the Mast website lists the intake runner as 305cc not 288cc? Please confirm?

CAMSTER

iTrader: (10)

Utilizes the Gen IV LS7 valve-train and intake manifold.
• Designed for any new Gen IV short-block with 4.125" bore or larger.
• Uses a 2.250" intake valve and 1.600" exhaust valve
• Has a 305cc intake port

If Cary is rite, then above statement from Mast is wrong, and if not the 274 cc Mast heads indeed outflow the 305 cc cnc castings across the chart, even with much smaller intake port volume, when compared the two flow charts, side by side...

274 cc 305 cc


lift int exst int exst
.300 245 171 234 159
.400 307 212 304 200
.500 350 229 356 228
.600 379 245 379 243
.650 388 247 379 249
.700 395 249 388 352

Pumba

I realize that you have made your mind up to use one of the two cylinder heads mentioned in the poll.

For those who are undecided, there is another cylinder head they may wish to consider it they are buildinga big bore, large cubic inch LS motor. West Coast Cylinder Head's ALL PRO LSW-1 heads.

I don't know what the GM LSX LS7 heads flow. The Mast 305 cc LS heads and the WCCH ALL PRO LSW-1 heads flow as follows:


MAST 305cc LS7 ------------WCCH ALL PRO LSW-1 - 285 cc intake - 108 cc exhaust

Lift------Intake---Exhaust---------Intake---Exhaust

0.100 ---- 75 ------- 55 ------------ 75.2 -----54.3

0.200 --- 155 -------108 -----------154.7 ----109.1

0.300 --- 234 -------159 -----------242.2 ----162.1

0.400 --- 304 -------200 -----------309.0 ----212.8

0.500 --- 356 -------228 -----------354.8 ----240.9

0.550 --- 376.5 -----236 ---------------------------

0.600 --- 379 -------243 -----------382 ------254.7

0.650 --- 379 -------249 ---------------------------

0.700 --- 388 -------252 -----------403.3 ----261.0

0.750 --- 395 -------255 -----------410.2 ----262.4

0.800 --- 401.5 -----258 ---------------------------

0.900 --- 406 -------260 ---------------------------

1.000 --- 410 -------263 ---------------------------


Just some data so we can all make better, informed decisions.

STROKER R/T

all pro ! wcch !! all day long !