Promaxx 370cc Cnc Ported Heads Review With Real Flow Numbers

[@Finding_K_Factor]

Well Mr Weingartner you do not “suck”.😃 I do appreciate your honesty and willingness to educate fairly. Even though currently I am “married” to a set of good “781’s” I appreciate the work you have done with the Pro Maxx 290, 317 and these 370’s. If at some point I decide to move forward with a set of aluminum heads for my 4.320” 468 the 317’s with a good valve job might be a worthwhile upgrade. Thank you!😎

[@r6duck]

Appreciate the honesty Eric. Affordability is a big consideration with a lot of racers. Learning what works is the best info.

[@johnstewart3937]

Great video as usual please keep giving us your honest opinion , it is what the world needs more of , its not always easy to tell people what they need to hear instead of what they want to hear but everyone is better for it , thankyou,

[@edpetrocelli2633]

I put a set of those on a street 55 chevy, 540 cid. 10:1. 653 torque 722hp solid flat tappetcam, my customer loved it. Those heads for the price ain`t bad.

[@brentsmith9121]

I’ve bought 2 sets of the 370 shockers ran one set on my 632 and the other set on my blown 565 both engines made great power the 9.5:1 632 made 770 hp / 840 tq the 565 made 846 at 5 psi

[@dominicmizzi4279]

Those heads would still make good power, I would imagine it would be easy to make 100+ hp per hole with 565 inches, 11:1, 274@ .050, with a good intake or a tunnel ram.

[@tomtowers8513]

Not sure if Mark Jones (AKA "Vortecpro") is still in the engine building game? He was the man for porting cast iron bbc heads and making good power with them.

[@leonardfoster6252]

I built a 496 with the Pro Maxx 340cc heads, it made 820 hp. at 6,700rpm... My 468 makes 800 hp. with Brodix 310 cc heads, not CNC'd. 108cc combustion chamber... 12.3 comp. ,50° valve job. 317cc's might be too big for the 468... Car goes 5.62 at 123 mph. in 1/8th and 8.82et. at 152.52 in 1/4 mile ...

[@turbodarealist4689]

That 468 ran 562 was that all motor ???

[@stevesolo16]

I ended up getting Brodix Race Rite 365s with intake valves at 2.375 .Mike Weinle is putting in the larger valves and mildly porting the heads. Eric, have you ever had the chance to flow these? It was hard to pass up Weinle Racing price for quality name brand Brodix heads.Eric, I'd like to see your take on these.

[@WeingartnerRacing]

The old adage is usually true you get what you pay for. I haven’t seen that head with that size valves.

[@GaryWhipple-q6w]

Wish you would tested them on superflow for comparison

[@WeingartnerRacing]

It takes too long to do. My superflow 750 takes forever to spool up.

[@chevyrc3623]

Yeah the budget size so I am with everyone who is on a really tight budget. Like my Sprint car in the hunt Wingless Spec Sprint tour my car is the most budget built motor and car and I still came out rookie of the year and 11th in points now yes granet the rookies didn't run every race and I wasn't the fastest rookie but I pulled threw all year running what I had and hopefully next year will be much better. And I can't wait to be faster out there

[@andy347495]

do you do valve jobs and install bigger valves on cast iron heads?

[@GaryWhipple-q6w]

Bought pair of them bare unused for 900bucksflowed alittle better on our super Flow bench.put on my 564 ci made good power 11 compression 715 lift cam . didn't Dyno it but ran 614 eight mile at 3500lb truck at Darlington

[@theshed8802]

Good review Eric. I buy a lot of stuff out of China for a few different reasons. I'm in Australia, and by the time anything American gets to me, it's about double the US retail price. I've been very happy with the quality of the Chinese castings, porosity is something that I essentially don't see. Unlike a lot of the American castings that I have had. When I'm not doing max effort stuff, budget is always a consideration. A lot of the name brand US stuff isn't actually being made in the US anyway, and the quality for the price equation isn't that good. Max effort stuff needs the best, so the extra dollars isn't that relevant to the conversation. Saying something is substandard simply based on racist bias is self delusional, which are most of the comments that we see made. I'm no lover of China, but I am a lover of value for money, and I've been to China, and I've been through a number of factories there. What I can tell you is that IF you are getting poor product out of China, blame the importer. They manufacture to the price point that the buyer wishes to pay. A company that I was working for some years ago was buying wheel bearings out of China, because they lasted better than the name brand US bearings that we had been using. There was a price difference, but for us that was just an added bonus.

[@GaryWhipple-q6w]

Probably should measure cc IVe got a set mine measure 352 cc .mine Flow 42o s at 800 on superflow 600 .lift. what would you do to improve them

[@DanClayton-fo6wt]

I poured the head in the video at 366cc long runner

[@jakeblack4095]

Those are nice looking for sure! You make me laugh at you not porting cast iron! Question why don't you use an exhaust pipe for exhaust flow testing?

[@WeingartnerRacing]

Because it lies to you. I did a video about it.

[@stevesolo16]

Eric, have you had a chance to run these on the dyno?

[@WeingartnerRacing]

No. Not many companies don’t all there heads for me to test. I’m lucky to get a set.

[@stevesolo16]

Integrity at a price. @@WeingartnerRacing

[@DanClayton-fo6wt]

​@@stevesolo16 I did. Pump gas 598ci 906hp @6400

[@timothybayliss6680]

They took a 317cc head and cut 50cc of metal out? Thats a bunch...doing some rough calculations the average material removed from the port wall is just over 0.060. Edit..the intake valve is maybe a bit small for a 370cc head, a 2.375 with a 50° seat would prob up the intake flow a bunch

[@ecc5119]

Cast iron makes hp

[@morganpowell2999]

I get the whole don’t support China thing, because I agree. But I think promaxx does good work on the Chinese cast, and I think most of your money when you buy from promaxx still stays here in America. 🇺🇸

[@stevesolo16]

I do business in China. I have walked into huge/big/small/tall/short/etc... shops that will blow you away.. Don't think they are backward, they most certainly are not. I understand the issue between there cylinder heads with sub par performance. Sorry, I don't want to share this to anyone right now. We will let them figure it out.

[@SealofPerfection]

It's just the casting, which is as good as anything cast here. They make heads to the specs of whoever is having them made. Heads are all about the machine and assembly work, which is all done here, by Americans, using good parts. I wouldn't trust heads assembled in China using offshore parts, but a casting is a casting, pretty much. Pro Maxx is in Alabama and employs a lot of Americans and does everything but the casting here. No issues with where these are cast at all, not with me.

[@mohanperformance.enginerd.1308]

Lousy numbers for a 370 cc 2.350 valve head. I think its partially like 440 mopar head syndrome where the valve is to chamber shrouded to make work well with a large valve and large csa. If the air runs into a steep chamber wall and cant get out. The greatest port in the world will still suck.