speedbird1229

Hi!

I'm rebuilding the 350 engine in my 79 and it's going to be a 355 cid engine bored to 0.030. I will have new pistons, probably flat tops with valve dishes. I currently have ported and matched 801 heads from Chevy 305 which I would like to use for the coming Summer. Their chamber size is 58 cc, 1.94 intake valve and 1.5 exhaust. I have calculated the compression ratio to be between 11 to 12 : 1.

Intake is Edelbrock Performer RPM and I have the 750 CFM Q-Jet carb but I might replace that, don't know yet.

Exhaust: Hooker Full length headers, then straight pipes out from the sides

4-Speed Manual transmission, should be the 3:36 rear end.

I'm looking to get around 350-370 HP out of the combo. I want the nice choppy idle. I was firstly thinking of Comp Cams 292H cam but I've been reading it's too serious for such engine. People have also suggested this: http://www.lunatipower.com/Product.aspx?id=2325&gid=297

Maybe you can also suggest a custom cam maker who can do what I need according to my engine specs?

I'd appreciate any advice! Thanks.

Crepitus

The Lunati looks pretty close. It should work well with the stock head. Nice all around Hot Rod build in the HP range your looking for. If you want to nail it the first time with top shelf parts and no wasted motion this guy knows his biz...

jonescams@bellsouth.net
http://www.jonescams.com

speedbird1229

Thanks for this info! I'm glad to hear the Lunati would work. Do you think the next one http://www.lunatipower.com/Product.aspx?id=2326&gid=297 would be too much for my application? Not even talking about the 284/292...

I am contacting Jones Cams right this moment just to see if he can help me and maybe I can get a deal from him instead.

cv67

Mike will do a great job for you. Only thing limiting your power is the small valve/head. Sure whatever mike does for you will get it running its best.

Dont know about giving "deals" they have their set price for "what they know". He is fair on the $ end though.

speedbird1229

I see. Thanks. I know the heads are somewhat problematic but at least they increase the compression. I want to build the engine so that I can install some 62 cc aluminum heads later when I feel ready for it and then I don't want to change the rest of the engine ofcourse again... I better optimize the other components for the possible new heads and suffer from some performance loss meanwhile with the 801 heads.

cv67

If youre dead sure of the upgrade I wouldnt get a custom cam til you get them. He will need to have an idea of what they flow .
Tell him your plan see what he recommends. Keep us posted

speedbird1229

I see. I will let you know since the e-mail was sent some hours ago and hope he replies soon.

Matt Gruber

have to calculate the EXACT CR.
it could be 10.4:1 to 11:1 or ?
that is too big a range to play "guess what cam"
.sounds like a fun experiment to see if it will run on pump gas. i hope they are forged pistons! i see, no mufflers? so it is a race car using race gas?
.
what is the head port size?
what do they flow?

63mako

With 11 to 1 or 12 to 1 compression a 268 cam will detonate the pistons out of the block. By the time you get a cam in there that will run on pump gas your 3.36 gearing will be an issue. High compression needs a big duration cam which needs low gearing. If you have 3.36 gears and want to run that 268 Lunati cam get compession below 10 to 1 with aluminum heads.

gkull

I ran a 355 ci with a H-flat lifters to 7200 rpm all the time using 135pound on the seat springs


Higher compression follows the laws of diminishing returns. from 9.5 to 10.5 is the biggest gain 10.5 to 11.5 is minor gains.

Intake cubic feet per minute is the ultimate decider of max potential power. I have ran over 310 cfm intake on 355 ci (ported Dart 230 cc)

I would recomend more like 195 - 210 cc on a 355 ci

speedbird1229

Thanks for all the advice. I am now in contact with Mike from Jones Cams and he suggested:

Part# H70330-72334-108
224/232 @.050"
.495"/.501" Valve Lift with 1.5 rockers
108 LSA
Cam Price: $249.69

Lifters, Part# J842H, Price: $89.83

I will give you the exact numbers for compression ratio. I will maybe also need to measure the 801 chamber size and see if it really is 58 or maybe it's bigger.

Forged pistons - do I need them in my configuration? I was thinking of going hypereutectic.

It's not a race car, it's a car which I want to be somewhat race-like. I am planning to run it on the highest octane pump gas possible here which would be around 93-94 in U.S. terms.

63mako

Really need to nail the compression down. If you have a true 11 to 1 there is no way the cam Mike Jones recommended will run pump gas. It will run in a carefully built 10 to 1 aluminum head engine. You need to keep your DCR under 8.5 with aluminum heads, less if everything is not absolutely perfectly planned to reduce any prospectuive detonation issues. 10.5 to 1 well built with aluminum heads needs 280+ intake duration if your running 112 LSA. 108 LSA requires more intake duration. Nail your compression down exact before you order a cam. Then nail your DCR down and optimize your build to avoid detonation issues. The cam Mike recommended needs under 10 to 1 comp as does your gearing.

Matt Gruber

HP?
measure the pushrod pinch area in the intake port. give me the HxW and i'll figure the ~max HP based on a formula in Vizards book on cyl heads.

Crepitus

I didnt pay any attention to the CR. That setup needs about 9.5-1

MotorHead

I know 2 people personally that have removed that 290H cam from there engines, cam is probably OK for certain things but you need to calculate DCR before you go any further. Gkull would love to see that hydraulic cammed engine at 7200RPM the lifters must have been packed with stacked dimes ?

Solid LT1

Where are you driving your Vette? I'm wondering if there is an Autobahn like high speed road system in Estonia? If your only driving back country roads you might want the next smaller sized Lunati cam but, the one you picked out will run very well on a compression from 9:1 to 10.5:1.

If your replacing pistons go with FORGED! I will no longer build motors with Hypereutectic pistons in them, bad thing happen when the detonate and they even seem to crack after long service use. We are seeing high mileage motors with Hyper Kieth Black pistons comming in the shop with cracks due to what looks like fatigue. Stock cast aluminum is more malleable and dosen't seem to have this problem. Some of these motors were built during the early era of Hyper "hype" when we ran tight piston clearances based on manufacturer recommendations we know better now. Even Kieth Black who is now Icon pistons had to admit defeat and start producing a new forged piston line as "Hypers" aren't all they are touted to be.

macka75

I have a 355 with AFR 190 68cc heads flat tops,decked block.
Ihave the Lunati 60103 cam
4speed 3.55 diff
This works very well

TedH

Instead of adding the flow-restricted 305 heads, have you considred flat-top pistons or a slight dome? The cam will be too much for those 305 heads.

If you are set on the 305 heads, keep your stock cam and just install the heads. The big(ger) cam shouldn't be added until you have heads that can support it with improved flow.

cv67

EVen ported you can only get so much air through XX size a valve so cam and expect it to run a certain way thats about it

63mako

Hate to repeat this but feel I must, That cam will not work on a 10 to 1 iron headed 350 let alone a 10.5 to 1. I would look at 9.5 to 1 or less with iron heads and about 10 to 1 max with aluminium unless race fuel is a viable option all the time. Putting the 305 heads on is a waste of head gaskets.