I don't have a roller block does anybody know what the closest to a LT4 hot cam there is? I can't afford to convert to a roller so I would like to know whats close.

I have a 355 4 bolt main
flat top pistons
vortec heads
sdpc vortec tpi intake
chrome slp runners

I want to make the most streetable power I can

Any cam ideas

Thanks

Greg

 

> http://store.summitracing.com/partde...3&autoview=sku <

 

if you're going to run the LTR setup, the hotcam or something similar isn't for you.

 

I don't know all the terms. Is LTR Long tube runner. Well what be your suggestion. It is not a roller.

 

LTR does refer to long tube runners. .....I know this is going to be one of those epic threads where all different opinions come out....

......BUT, I've heard, read, researched, and there's a certain area that seems to be the limit for the LTR intake. 'Bout .510-ish on lift, and about 210-ish degrees of duration. Now that's not to say a little more is too much, but it's a ballpark. The LT4HC is .525 - 218/228 cam

The higher numbers allow more air, but at higher rpms. The LTRs can't flow that much air, so the intake fails where the cam shines. It's all about matching parts.
----------
.....for the record though, given your mods, I don't think the LT4HC is a horrible choice. I might go a little smaller myself, but I don't think it's ridiculous.

 

If I am not mistaken Abubaca, the .525 lift from the hotcam is if you have 1.6 rr's, I think it is .490's if you have 1.5's which is stock.

 

OK so if I take those numbers and apply them to a hydraulic flat tappet cam will it be equal to lt4hc or does roller change the performance to where you need more dur or lift with flat tappet cam

greg

 

Ive had owned and built both roller and flat tappet
engines, and both work very well if they are applied
in the right build.

Obviously roller motors have benefits, such as
less friction, smoother acceleration/idle, & higher
RPM capability, they are also very quiet (internally)

It wont hurt you much if you cant afford to go
roller, as flat tappets made power 20years ago
just the same.

You can use that as a temporary fix until you
can go roller, or something different altogether.

Again, My opinion.. I think your ok, but the LT4
hot cam or equilivlant would not suit your tastes,
even if it was a LTR roller motor.

Find a cam with a wide bandwidth of torque
through the RPM range, with uptop potential
beyond 5500-6k RPM.

Last thing a TPI engine needs to be is gutless
at 1500/2000rpm..I ran a cam with alot of overlap
and makes the torque I need (for now) lift is a
meager .465, but I make my power low/mid range.

But yea, people might think different, but
flat tappet motors are fine to build, If by
chance you cant go with a roller application.

 

OK so the LT1-4 tpi unit is not a ltr. And mine is so the hotcam is not a good choice.

TPI- What cam do you run?

 

Oh, Im confused..

Your not running long tube runners? you have a LT1
unit uptop (no runners?) If thats the case, then you
should be able to breathe enough uptop for the cam,
but again someone should have more insite about it.

I thought you were using a stock/modded TPI unit, I
overlooked your post.. please excuse me

I thought the cam described wasnt the best fit for
a long tube runner TPI setup, as power is distributed
in the lower/midrange RPM band.

I run a hydraulic roller, streetable and a great idle.
I had gotten this cam for free a few years back, a
Crane grind, I believe, specs as follows.

Cam Style: Hydraulic roller
Basic Operating RPM Range: 2,200-5,200
Intake Duration at 050 inch Lift: 224
Exhaust Duration at 050 inch Lift: 224
Duration at 050 inch Lift: 224 int./224 exh.
Advertised Intake Duration: 282
Advertised Exhaust Duration: 282
Advertised Duration: 282 int./282 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.465 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.465 in.
Valve Lift with Factory Rocker Arm Ratio: 0.465 int./0.465 exh. lift
Lobe Separation (degrees): 112
Intake Valve Lash: 0.000 in.
Exhaust Valve Lash: 0.000 in.

I have 305 081 58cc heads on this particular build,
so I thought the cam matched up well. I have also
installed Crane Energizer 1.52r roller rocker's with
no problems. (recently passed Arizona emissions)

Sorry for the confusion

 

roller has higher ramp rates and other variables that make them better, as mentioned in another post. you want something that'll match up with your intake, which makes power from 1000-5000 rpm. The hotcam is made for 2500-6500 rpm. see how the ranges don't match? you want a cam that's going to match up with your intake range, or go with a new cam and intake in one shot. if you're going to stick with the LTR setup, i'd consider the zz4 cam. I had that in my car with the LTR setup and it made tons of power, and can be ran with a stock tune. I would suggest a custom tune for the car reguardless of what cam you use.

 

TPI- I have what is described below. SLP runners on vortec TPI. Some how I confused You

 

"So the LT1-4 tpi unit is not a LTR, and mine is"

Sorry, dunno what happened

I somehow concluded that you didnt, hehe

I had it reversed.. I think adjusting to
the graveyard shift is getting to me !!

 

there's a few things i wanted to point out with this cam.
first, longer deration does make power at higher rpms, but thats only with larger lift. this cam has smaller lift, witch helps keeps the velocity higher. even at low rpms. (to make more power). this cam will work fine with your setup. trust me.

 

Thank you. I get really confused though. I have a 40 ford coupe with 010 4 bolt block flat tops any way I put a comp cam that is 260 with 440 and it is boring. I am not saying this choice is not right (because I don't have a clue).
But these other cams have bigger numbers. I guess the TPI is the limiting factor?

Thanks again

fj

 

Comp cams says my cam is old design no comparison.

What does computer controlled compattable actually mean?

 

it uses more LSA and less valve overlap to increase vacuum. there not bad, but most of them are designed to work with your stock computer so there very limited.