Building a 1956cc engine

[André_82]

Hello to everyone,

I am currently planning / started building a 1956cc engine for my 1969 late model.
Now I would like to hear the opinion or any suggestions of you guys.

Configuration:

-   used case in good condition and new line bored
-   76mm CB forged crank
-   reworked stock rods
-   90.5mm Mahle pistions
-   compression ratio 9.5 : 1
-   Engle W120
-   stock 1:1.1 rockers
-   CB straight cuts
-   CB lifters
-   1,5 liter oil sump
-   48 IDF / maybe ( for sure !! ) later I will change to 48 IDA !
-   ported stock heads with 35,5 and 32 valves
-   / in the future I will go with 40 and 35,5 valves
-   1-5/8”  merged header
-   clutch : KEP Stage 1
-   lightened flywheel

What venturi size I should use  ?? Planned is a 36mm venturi.


What do you guys think, will this combo work and how many horsepower will it make ??
Thanks André

[181]

go with IDAs directly or I would use 45 DRLAS instead. Also your heads..make it right for the first time!

[Zach Gomulka]

go with IDAs directly or I would use 45 DRLAS instead. Also your heads..make it right for the first time!

Agreed. You'll waste a bunch of money and time doing it twice!

[Jim Ratto]

Hi Andre, I would suggest going with 78mm crank. You can run stroker type 90.5's and not have to use much barrel spacers between cylinders and case, depending on what CR you want and what the heads cc out at. The 74 and 76 strokes do work fine, but you're kind of in between using a stock stroke 90.5 (like for 1776) and a stroker type. With the stock stroke you'll most likely need to space barrel away from case by at least .150"+, which causes adjustments (major) to valvetrain geometry (depending on rocker ratio) and cooling tin needs to be modded to fit tight. Or if you use stroker types on 74 or 74 you might have too deep of a deck, needing cylinders to be machined or heads flycut. The 78mm crank with stock rods goes together as easy as a stocker, provided the case is clearanced inside for the stroke and the rods are clearanced. I run a 78mm with VW rods, stroker 94mm's and the motor went together with no shims @ .061"
Hope this helps.
By the way, go for a set of 40 x 35.5 or 40 x 37.5 small port heads, and maybe step cam up to W125 Engle. Sarge in DKP runs a W125 in his 90.5 x 78 48IDA motor and it is silky smooth and it gets up and goes hard. The W120 is a good cam for 1835cc or under. For a hot street car with bigger cc it's a little mild. You might talk to Jeff Denham (ugly duckling) about a set of "Harry" heads...he'll know what I mean.
44IDF, 48IDF, 45DRLA, all of those will work well on the street, as will 48IDAs. I would suggest a 36-38mm vent for street and good hp to 6500rpm, based on 90.5 x 78 with nice heads and Engle 125
have fun
Jim Ratto

[Neil Davies]

I'm glad Jim typed that - he's said everything that I wanted to but he has the experience to back it up too! I'd go for the 94's over the 90.5's too, you're getting the case and heads machined anyway, so why not go big? 2165cc is a great size! The only reason my 2007 is that size is that it was bought complete!