We are just about wraped up with my new heads/intake setup. Should be able to start putting them on the car here very shortly. Steve(SAR2K) gave me a compairison between my old ported lt1 heads and my new Steve Stumph/Thunder racing LT4s.[CODE]

lt4 in. LT1 in. Diff. Lt4 Ex. LT1 Ex. diff.

.050 036.3 34.20 +2.10 29.30 29.40 +.1
.100 064.2 61.70 +2.50 58.60 55.60 +3
.150 094.8 89.80 +4.90 88.10 82.60 +5.5
.200 125.4 118.9 +6.90 114.7 102.5 +12.2
.250 154.8 148.0 +6.80 137.4 119.1 +18.3
.300 181.2 175.3 +5.90 151.2 133.0 +19.2
.350 206.3 198.0 +8.30 164.6 144.3 +20.3
.400 227.7 216.1 +11.6 174.5 153.1 +21.4
.450 245.1 230.9 +14.2 182.0 159.8 +22.2
.500 263.2 241.3 +21.9 187.8 164.8 +23
.550 279.1 235.8 +43.3 192.2 168.8 +23.4
.600 288.7 233.1 +55.6 196.4 171.8 +24.6
.650 285.7 231.9 +53.8 199.4 173.7 +25.7
.700 283.0 230.0 +53.0 202.2 175.0 +27.2
[/CODE]
I'm really excited about the changes on the car and what we think it will pick up. Remember that my cam is fairly large solid roller with lift in the 650+ range so I can use these new much better flowing heads up high and that I made 439 rwhp on race fuel and 428 on pump gas...going through a 9" with 4.71 gears. Who knows where we can take this little 355. Its going to be hard doing battle with the full race car auto ls1s in the Thunder shootout but hopefully we can hold our own..or at least let them know we were in the race.

Just though you guys would like to see the new numbers. Steve told me my best port peaked at 298 range with all of them in the 293 +/- a few cfm on the other ports. This was between .600 and .650 lift but we didn't include them on the chart. Also this is still a fairly small intake port(for an lt4) so the cfm/CC is still very good and we like the numbers we are seeing.

Tim

 

I don't know why the nubmers are all being smashed together when it is posted..they are fine when I typed it. Oh well..hope you can figure it out

 

Looks nice. Hopefully those will translate into some really great track times.

 

you should definetly see some improvement, the 355 should use the large runner volume pretty well too, so I doubt you'll have any problems with volumetric effiency, plus your mid lifts are killer with those lt4's.

 

I'm interested to see how it will run. Did you flow the lt1 heads after removing them or are those old #'s and were they all from the same bench?

 

my lt1 mid lift #s are a bit better than those lt4 #s but a at .550 lift the your #s just jump past mine, but you exhuast is is a good bit better. but i also used 2.05 intake valves.

what was the intake runner size after porting, my lt1s ended up a t 205cc

who did the heads. LE did mine.

and what kind of bench were they flowed on.

and what lift cam are running.

and please post back some track times.


lift int exh

.0500 36.5 27.0
.1000 67.4 50.6
.1500 104 78.7
.2000 138.6 166.2 ??? this must be a type O
.2500 167.4 128.0
.3000 194.4 144.5
.3500 224.3 156.5
.4000 245.0 167.3
.4500 259.7 174.1
.5000 268.6 180.7
.5500 273.7 186.3
.6000 276.4 190.2
.6500 277.4 192.5
.7000 274.2 194.4

 

I'm wondering if the LT1 head #s were after the removal from the motor?

Either Way your LT4 heads have some excellent flow!

 

[CODE]
lt4 in. LT1 in. Diff. Lt4 Ex. LT1 Ex. diff.

.050 036.3 34.20 +2.10 29.30 29.40 +.1
.100 064.2 61.70 +2.50 58.60 55.60 +3
.150 094.8 89.80 +4.90 88.10 82.60 +5.5
.200 125.4 118.9 +6.90 114.7 102.5 +12.2
.250 154.8 148.0 +6.80 137.4 119.1 +18.3
.300 181.2 175.3 +5.90 151.2 133.0 +19.2
.350 206.3 198.0 +8.30 164.6 144.3 +20.3
.400 227.7 216.1 +11.6 174.5 153.1 +21.4
.450 245.1 230.9 +14.2 182.0 159.8 +22.2
.500 263.2 241.3 +21.9 187.8 164.8 +23
.550 279.1 235.8 +43.3 192.2 168.8 +23.4
.600 288.7 233.1 +55.6 196.4 171.8 +24.6
.650 285.7 231.9 +53.8 199.4 173.7 +25.7
.700 283.0 230.0 +53.0 202.2 175.0 +27.2[/CODE]


since im such a nice guy, here ya go...

in the future, wrap [ code ] tags around anything that you want to keep space formatting on.

 

The old head numbers are after we pulled them off the car. both were flowed on the same bench..a SF 1020 at thunder racing. Their bench is actually known to flow low compaired to other benches.

Steve Stumph(SAR2K) at thunder racing did all the work/porting to the LT4 heads(my old lt1s were ported by a local guy that no one here will know) I can't remember the exact runner volume...hopefully steve will see this and post up some information. I'm runniing a 656/628 lift cam and the HP numbers/times in my sig were with the old heads/lt1 intake setup.

 

That makes sence on the LT1 heads,

MAN those LT4s must flow some serious air, you should see a huge improvement from them alone!!!

 

Looks good. What size/brand valves?

 

2.05/1.56 manly race flow.

 

The runner size is 215cc. The bench is a Superflow 1020.
As you can see these heads are set for mid and upper flow given Tim's cam and the RPM the engine sees on runs (7,000+). Originally I was using a 2.00" valve, but decided to test out a 2.055". This switch gave up 10 cfm in the mid range, but gained 20+ from .585 on up which this cam can obviously use. Only downside is that the larger intake seats will keep me from milling the heads to get the same compression as the old heads. We're giving up .5 in compression, but gaining a hell of a lot of air flow. Should be interesting to see the track results... hopefully in the next two weeks.
I have a feeling someone will be going FAST or DFI soon. LOL!
Steve...

 

nice numbers.

Did you ever figure out what lifters you have?
I'm still trying to decide if I should use these crane solid roller lifters I bought from Thunder Racing

 

I pulled and looked at them...no numbers or any identifying marks. I think they are comp lifters. They are a half body lifter with a link bar. They are just like some lifters thunder used in a stroker lt1 they have at the shop.