I have a set of MTI heads and intake sitting here and I was thinking about doing a h/c set up. The thing is I have always liked blower LT1s, back when I was in high school those were the cars I saw tearing up the streets so it kinda left a mark on me. Any case, I was thinking about start building a short block specifically for boost and later on buying a used T trim for the car. The heads I have a re decked to 51ccs and I would like to be around 9:5:1 CR, my power goal is about 550-600rwhp on pump 93, I want to be able to run 10s am I talking out my *** or is this possible? Would I be better off investing in building a 383?

 

A 355 LT1 is what I have. Because it's a smaller motor, you need more boost to get big power. Your target 9.5:1 compression ratio is too high. You need to get between 8:1 and 9:1. This will probably let you run pump gas.

Make sure you get a blower specific camshaft and a good valvetrain and use head studs. Of course, the bottom end must be built to handle the extra boost, depending on how radical you want to get.

I would consider getting the Vortech Ysi for big boost and power, 12 lbs and up. You could underdrive it a bit with an 8 or 12 rib pulley. It has a very high adiabatic efficiency of 78%. I would just skip the t-trim.

I am very happy with the Vortech V2. It's really quiet and makes good power. Great street blower.

 

Thanks man but a Ysi would deff be out of my price range and I honeslty just want to run 10s. when I start looking for a blower I will be looking for a used kit also and I think even an S strim could get me to my goal. Although we have a LT1 Firehawk down here running 9.90@137, 1.6 sixty, 396 with AFRs ona T trim, Vortec after cooler, 3700lb full interior including the back seats, heat, a/c, roll bar has some 26 inch slicks on it and a set of Fikse 17X9 Mags up front because the car has Baers on it. To me thats like the perfect street car, I see taht car on the street all the time.

 

The T trim should be fine for what you want to do. Personally, I went with a 383, but then again, I have 60cc heads. Either way should get you into the 10s though as long as the rest of the car is up to the task.

 

The compression is not a problem you just have to match the CR with the boost level and how fast it comes in.

If you have a choice a .020 over setup is better than a .030 over setup since you will have more cylinder wall thickness.

More cubes means you need more blower to make the same boost so a 355 will do the job as well as a 383 with less stress on the rotating assembly.

Bret

 

I'm in the same boat with CR; my heads cc'd at 52. With a deck height of .015 and -20cc pistons on a 355 and .039 fel-Pro's the static compression came in at 9.7 to 1. I was counting on around 9 to 1, but with the thinner gasket and reduced chamber volume, it was higher. How can we lower our CR without replacing the pistons? Are there any good gaskets out there at .50 or thicker that will hold mild boost?

Neil, I'm not trying to highjack, I just thought it was relevent to your situation..