Thread: 3.5 V8 High comp or Low comp?

Hypereutectic pistons dont expand when you get them hot , that is why they are used !
A special grind cam ? you going to degree it in properly when you fit ?
A High rise manifold ? What do you expect that to do ? dont you mean a Single or dual plain manifold ? A 4 barrel Carb ? that was suitably matched to the heads.
All of which wont do anything , unless you have the heads properly ported .
There is huge difference between all the home head port jobs and getting it done professionally . With severely port choked heads like yours , changing the rest wont make any difference , except chew alot more fuel .
A lttle something from a real Head Porter
How do you set up a port for the correct air speed vs Engine size & RPM? How do you determine your ports don’t end up in port choke? The cfm off the flow bench may not tell you! Neither will guessing or grinding by eye without measuring & setting the ports up to specific sizes. A modern cylinder head must be efficient, be it CFM / Sq in, Discharge co-eff’ velocity, Pressure Recovery, Mixture Motion. This is what CHT specialise in, with over 20 years experience of racing & cylinder head modifications. It’s experience that counts & that’s how CHT can help you. Correct sizing areas to set Mach speed velocity which is paramount to horsepower production at the desired RPM without going into port choke at the minimum cross sectional area or at the valve curtain area. Fine tuning of valve seats. Port mapping & designs. Combustion chamber modifications to control detonation. A popular saying is: Make it flow as much as possible! Sounds good, but it can be a torque and HP disaster if you don’t know what you’re doing! Too much CFM can be a bad thing if the min CSA is too small and the pitot pressure is higher that your test pressure. Port choke with a fairly large HP/ Trq loss will be the result.
Not hard to get your little 3.5 Heads out to 300HP potential , up to you how much of that you want !,only issue will be the $$$$$$$$$$$$$.

Originally Posted by Squigs

Gday phillip I have just purchased a 76 2 Door Rangy non detox 3.5 what advise can you give me on making this motor perform better it has extractors already a non standard cam bought from rover tech standard carbys standard ignition this engine drinks fuel lacks power. prevoius ford v8 owner now wont to learn the v8 rover stuff by the way i am a mechanic of 30 yrs exp..cheeers Mike

I had an after market cam in my V8 and it really lacked performance. I installed a pre-pollution cam from an early Range Rover (up to 1975) and it really improved the torque through the whole rev range.

Edward

Originally Posted by I Love My Landy!

I had an after market cam in my V8 and it really lacked performance. I installed a pre-pollution cam from an early Range Rover (up to 1975) and it really improved the torque through the whole rev range.

Edward

Try using Wade Cams 259a grind, works best with high compression. Brings max torque down from 3700rpm to a more usable 2500rpm.
Yes the intake manifold is shallow to keep motor under the fairly shallow bonnet height, keep the standard inlet rams horns to air cleaner this helps to keep air velocity up for improved torque. Keep your primary pipes on exhaust headers to 1 5/8" for mid range. My last 3.5 10:1CR with HS6 SU carbs regularly achieved 27-29MPG on the highway with the above cam and kept up with a mates 4.9l stoker!