Have a few questions about a 355 im putting in a 86 iroc. First the specs of my build.

Fresh 92 SD 355 with a mild cam and full bolt ons. 700r4 with 3.23 rear. With the following parts sitting on a shelf:

World heads new in box, which I will have ported.
http://www.summitracing.com/parts/WRL-043650-1/
Corvette Intake: stock base, lingenfelter runners, bbk throttlebody, all ported and portmatched by lingenfelter.

Now for the questions-
1. Will I have to enlarge holes or use shims to use the corvette intake on the world heads? The heads are stock replacements for centerbolt heads

2. What is required to use my map sensor on the ported maf plenum?

3. Can the 1.94 1.5 world heads support high hp if ported?

4. Any cam recommendations?

Thanks in advance,
Garrett

 

Those are not high performance heads and they will greatly limit the potential of this build. I assume by "Lingenfelter runners" you mean the Superram. The Superram will outflow those heads by a fair margin. The combo will work but your low end torgue will suffer as you will be losing some intake velocity at lower engine speeds. I guess you could also mean the Edelbrock runners that are offered on the Lingenfelter website. These are not a Lingenfelter part. The Edelbrock hi flow runners will work better with those heads. Either way though, the heads are what will limit your power. These heads like most any will benefit greatly from port work. It's unfortunate that they have the larger 67cc chamber but you can deal with this through milling or head gasket selection. You want about 9.5:1CR with cast iron heads.

As far as whether the intake will bolt up to the heads, if these are direct replacements for the L98 heads, they will have altered angles on the 2 bolts closest to the center and the intake base needs to have matching angles at these locations. Since you're using a stock Vette base. I'm going to bet that it will have these angled bolt holes. Other wise, you will need to modify the base to work. The spacing of the holes is the same either way.

To connect a MAP sensor to the MAF plenum, just drill and TAP for a 1/4" pipe and install a /14" pipe to 1/4" hose nipple. The fitting should be placed towards the rear of the plenum so that the hose to the MAP sensor will be as short as possible.

For cam recommendations, I tend to go for the larger lobes. However, if you use these heads as they are, you will want to stay down in the 210-220 range for duration at .050. I don't know what the max lift is on the springs provided with the heads. There seems to be two options, one uses 1.44 dia springs, the other uses 1.25 dia springs. You have to figure out for yourself where coil bind is and what spring options are. Generally speaking, in the 210-220@ .050 range, you're going to be looking at .480-.500 lift with a fairly aggressive hyd. roller cam. You can increase the gross lift by going to 1.6 rockers. I assume you are going with hyd roller and not flat tappet. If you are going flat tappet, good luck with that.

My advice would be that you at least consider sending those heads back to Summit in exchange for something with a 190cc intake port. If the block is an early design(non factory roller) consider going with a retro roller kit. It will be money well spent. This is of course my opinion only.

 

The runners I believe are acccels. They look like this https://www.yearone.com/Catalog/Show...=861&pgid=3128
The whole tpi intake was sent to lingenfelter in the 90's for porting.

The heads I picked up new for $300 which is the only reason I was considering them. I was hoping with porting they could support a nice cam. What type of gains are typical with head porting? Currently 171 runners how big after porting? Are the 1.94 valves a major restriction? It is a roller block so i'd be going with a hyd roller.

Thanks

 

To have iron heads professionally ported youll spend 800-1000 easy.

Adding larger valves seats valve job etc at least 2-300 parts plus machine work. not counting any little stuff

At the end of the day you might wind up with a very expensive set of 240. 250 cfm heads

For the same $ you could get a nice set of AFR 180s that will trounce them in every area. Small valve heads wont support any respectable amount of power.

Now if you were just looking to maybe eek a little more power over stock you could do "some port work" to yours and leave small valves in and pick up say 20-30 cfm but its simply not worth the money imo. Will it run better than stock, sure it will. You wont see the above #s with small valves

All depends on what #s youre truly after and what youre wanting to spend.