The Nostalgic 265 Engine Build

[bfalfa55]

I posted this before and was hoping I would get some of your thoughts. I have edited it and put a suggested cam from a Lunati rep. on the phone. Let me know what you think.

 http://www.gmperformancemotor.com/parts/10105117.html
I am thinking these gaskets will work well, I just have to get them and make sure they are a match with the areas the original engine owner modified on the top of the cylinder  bores. He scalloped areas to match the head gaskets he was going to use. Not the best thing for a little engine like this but they only take away 2cc's away from my compression but that isn't going to hurt me because I will be at 10.5:1 even with them. I am trying to see if I can just get them from a Chevy dealership parts counter in case they aren't compatible.

These will put me at a .043 quench. I also have a porting question for you guys. The flow numbers I have found for L98 Aluminum heads are just about right for this size engine as they are. Should I clean up all through the ports OR just do enough clean up to true up things and take out the imperfections ? I don't want to take away what little low end torque I will have so this is why I ask.

This is the cam I was looking at and ironically it is the exact cam Lunati suggested when I talked to them. Not purchased yet, ordering my gaskets so I can get to porting my heads.
Voodoo Retro-Fit Hydraulic Roller Cam & Lifter Kit - Chevrolet Small Block 270/278
[​IMG]
Product Description

Lunati’s Voodoo series of camshafts deliver more area under the curve than any other series of camshafts. This means more throttle response, quicker acceleration, more vacuum and better efficiency. These factors, combined with maximum horsepower and torque, make Voodoo camshafts the perfect choice for a wide range of high performance applications.Retro-Fit Hydraulic Roller. Strong power increase in mildly modified engines with excellent throttle response. Will work with stock converter in 383-up c.i.. Likes 2000 RPM converter in 350 or less c.i. applications. Likes 3.23-3.73 gearing. Largest choice for inboard/outboard marine applications. Has noticeable idle and likes headers.

Advertised Duration (Int/Exh): 270/278
Duration @ .050 (Int/Exh): 219/227
Gross Valve Lift (Int/Exh): .515/.530
LSA/ICL: 112/106
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1800-6000
Includes: Cam & Lifters (#72330-16)


Part Number: 20120711LK
Previous Part Number: 60111LK

Jobber Price: $605.56

[jeff/21]

i would do the valve bowls, a good valve job, gasket matching

[Roger]

It looks like the head gaskets with the stainless fire ring will work fine with your compression. The camshaft should idle fairly well and make power to 5,500 or even 6,000rpm. While the air flow of those heads look pathetic at first, your stock heads should flow close to the same amount of air needed to feed your 265” engine at .50” lift as a set of stock Dart Pro 1 230cc heads flow to feed a 383” engine. I say put it together with the parts you have using the cam you quoted and let us know how it runs.

[bfalfa55]

Alright engine gurus, how close to the bore should the fire ring of your head gasket be to the bore ? Due to the scalloped shapes at the top of my bores, the head gaskets I bought are right at the edge of them. I don't have a picture at the moment but thought I would ask first. I may be limited to a certain bore/combustion chamber shape since this was done to the block, so it brings up another question: How thin of a had gasket can I run with aluminum heads ?

[ricardo1967]

Alright engine gurus, how close to the bore should the fire ring of your head gasket be to the bore ? Due to the scalloped shapes at the top of my bores, the head gaskets I bought are right at the edge of them. I don't have a picture at the moment but thought I would ask first. I may be limited to a certain bore/combustion chamber shape since this was done to the block, so it brings up another question: How thin of a had gasket can I run with aluminum heads ?

1) I've always considered OK as long the fire ring doesn't overhang into the cylinder bore.

2) In my mind, minimum thickness is closely depended on gasket type (composite, steel shim, MLS, copper, ...), not cylinder head material.

Now let's hear the pros.

[bfalfa55]

I reordered my gaskets and will have to run a 4.125 bore, .039 gasket. This will give me a .054 quench and 10.15:1 comp. Taking .010 more off the block will put me at .044 and right about 10.5:1. I don't know if doing that is worth it or not for the effort. Thoughts ?

[Roger]

The block I just had machined measured 9.025” height stock. Add that with a stock .039” gasket and the quench from Chevrolet is .064” and they run fine. No reason it wouldn’t work with what you have, unless the deck surface isn’t flat. Unless you use some poor quality gas detonation shouldn’t be a problem I would think at that compression ratio.

Or spend about $150 to surface the block and use your gaskets. Milling adds about .35 point of compression which adds about 3 HP on a 300 HP engine. Check it out at this website. (Results are not absolute but it puts you in the ballpark)

http://www.wallaceracing.com/hp-cr-chg.php

Or if your deck surface is flat spend about $150 on some Cometic MLS gaskets with a 4.100” or 4.125” bore and .030” thick to end up with a .045 quench.

[bfalfa55]

Thanks Roger, that is what I was hoping to hear. The block has already been decked flat and I got my data from the same calculator from Wallace Racing ! I have been using a number of their stuff online, it seems to be pretty good, better and more consistent than some of the others I have seen and used. If I was trying to squeak out every ounce of juice for a race engine, I might do it. But this being more of a double duty engine, I don't mind some of the trades offs for a little street driving.

[bfalfa55]

Based on where my cam RPM range is 2,300-6,300 RPM, .218/.228 duration @ .050, .503/.503 lift. 112 LSA hydraulic roller, do any of you think I will benefit from an X pipe or an H pipe in my 2 1/4 inch exhaust system ? I read some conflicting information as to how it may benefit or hurt my little 265. I would like to hear your suggestions or if you think it isn't worth the effort at all.

[Frontenginedragsters]

 I don't have an opinion on the exhaust cross over.
I know this will open up a new slew of peoples opinion's but.......
I don't think that camshaft is going to make any power past 5000 RPM.
Now most of the small engines we dyno are 302 ci and bigger.

[bfalfa55]

I am interested in hearing why tou feel that would be the case. I am not arguing it, just gathering intelligent opinions.

[Frontenginedragsters]

I based my opinion on the last of 3 camshafts you mentioned.

Matt

[bfalfa55]

The RPM range I listed for the last cam came from talking with a Lunati rep. The actual range for a 350 chevy was 1,800-5,800, he said the smaller cubes would shift up 500 RPM. Did they give me miss information by telling me the RPM range would increase when it is actually going to decrease ? I have always been under the impression that the range has to increase to get more power out of a small cube engine. This engine will be just below 10.2:1, with the aluminum L98 heads, with 1.94/1.5 valves. With that cam and these heads, do you think it is going to choke cylinder flow by the time it is at 5,000 RPM ?

[Roger]

Take a look at a dyno test performed on a Chevrolet 350ci/290hp crate engine as delivered from Chevy to Westech and modified with only a RPM manifold and headers, then draw your own conclusions. The crate engine had 8-1 compression and stock iron 76cc heads with 1.94-1.50 valves. The camshaft specs from Chevrolet are:
    222*/222* duration @ .050”, .450”/.460” lift. 114* LCA hydraulic flat tappet
This cam is somewhat similar to the last two you listed but unlike those you listed it has the disadvantage of being flat tappet.
 
I have to ask myself if a modified Chevy 350 with a somewhat similar cam to the ones you listed can make 330hp at 5500rpm, then why wouldn’t the two last cams you mentioned work as well in your engine and rpm even higher due to its smaller size and increased compression. Can’t help you with the x-pipe deal, I use zoomies.

   Chevy 350ci/290hp modified by
Westech with RPM intake & headers
Horse Power       Torque        RPM       
       100             270#          2000
       160             280#          2875     
       240             345#          3750
       305             340#          4625
       325             325#          5250
       330             315#          5500
     (Figures pulled from a graph)

[Frontenginedragsters]

 I apologize for responding late to your posting.
Working at our shop by day and putting up a new building at night.
 Mine are only opinions because I have no dyno history with small bore engines.
I know we see improvement on air flow going from a 4.000" bore to a 4.060" bore and that adds power.
Your running an engine with a bore of 3.935". Reducing the 4.000" bore by .065" also would slightly reduce air flow.
Also the short stroke reduces the volume of air being pulled in.
If you lived a little closer I would cut you a deal on dyno time just to get the real answer.
Matt